Species with no country or region

Acanthopsoides sp. 'A01' is an unidentified dwarf horse-face loach of unknown origin, likely to be collected in Thailand or Peninsular Malaysia. Like several of its congeners in the trade it has proven very tricky to identify. It spends some of its time completely buried, so it needs a soft, sandy substrate, and it is best kept in a group of six or more. SF member Mark Duffill has recovered fry from an adult pair kept on their own in a small tank.

Acanthopsoides sp. 'A02' is an unidentified dwarf horse-face loach of unknown origin, likely to be collected in Thailand or Peninsular Malaysia. Like several of its congeners in the trade it has proven very tricky to identify. A soft, sandy substrate is essential because it spends some of its time completely buried, and it is highly gregarious and best kept in a group of six or more.

The big spot peckoltia (L163) is an undescribed suckermouth catfish collected from the Rio Pará in the Brazilian Amazon. Trade fish are often confused with the very similar L013, and the two are only easily told apart as they mature: L163 keeps its spotted pattern while L013 tends to become duller. It is placed in the genus Ancistomus. Newly imported fish should have a rounded belly and eyes that are not sunken.

The common bristlenose catfish, Ancistrus sp. '3', is the loricariid sold everywhere as the 'bristlenose', of unknown origin and bred commercially. It was once thought close to the Argentinian A. cirrhosus, but genetic data suggests otherwise, and some consider it a hybrid. Adult males carry fleshy tentacles on the head, and the species spawns in caves with the male guarding the brood.

Andinoacara sp. 'Orinoco' is an apparently undescribed cichlid from unspecified localities in the Río Orinoco basin, presumably in Venezuela. It was traded as 'Aequidens' sp. 'Orinoco' and, following Musilová et al. (2009), appears to be a member of Andinoacara. Relatively peaceful for a cichlid of its size, it is a biparental substrate spawner and relatively simple to breed.

The giant brochis, Brochis britskii, long known as Corydoras britskii, is an armoured catfish restricted to the upper rio Paraguay in Mato Grosso state, Brazil. It grows to around 90 mm SL and can be told from B. splendens and B. multiradiata, the other two species long kept in Brochis, by its 15 to 18 dorsal-fin rays. It forms aggregations in smaller tributaries and still waters such as backwaters, oxbows and marginal lakes.

Brochis geryi, long known as Corydoras geryi, is an armoured catfish from the Río Mamoré basin in Bolivia. Not commonly seen, it is one of the larger corys in the hobby at around 7 cm.

Brochis ornata, long known as Corydoras ornatus, is a larger armoured catfish from the lower Rio Tapajós basin in Brazil, growing to around 70 mm SL. Its habitat is not recorded and no captive breeding information is available. Very peaceful, it should be kept in a group over fine sand, with plenty of cover and well-oxygenated water.

The reticulated cory, Brochis reticulata, long known as Corydoras reticulatus, is an armoured catfish from the lower Amazon basin in Brazil, also known as the network cory. One of the commoner species seen in dealers' tanks, it is a good cory for the beginner. Very peaceful, it should be kept in a group of at least six, and like other corys it is sensitive to dirty substrates.

The flagtail cory, Brochis robineae, long known as Corydoras robineae, is an armoured catfish from the upper Rio Negro in Brazil, also known as the bannertail cory. It is found in the main river and its tributaries. Not the easiest Corydoras to induce to spawn, it can still be bred in a similar way to many other species in the genus. Very peaceful, it should be kept in a group of at least six.

Brochis robusta, long known as Corydoras robustus, is an armoured catfish endemic to the Rio Purus drainage in Brazil. It grows to around 95 mm SL, and as they mature males in particular develop an extended first dorsal-fin ray. It is not seen all that often in the trade, and in nature it inhabits small tributaries, creeks, areas of flooded forest and sand banks.

Brochis seussi, long known as Corydoras seussi, is an armoured catfish from the Rio Mamoré basin and Rio Poranga in Brazil, also referred to by its C-number, C027. Very similar in appearance to Hoplisoma gossei, it can be distinguished by its less rounded snout. Very peaceful, it should be kept in a group of at least six.

The false network cory, Brochis sodalis, long known as Corydoras sodalis, is an armoured catfish from the upper Amazon in Loreto, Peru, and Amazonas state, Brazil. It inhabits small tributaries, creeks, pools and areas of flooded forest. Very peaceful, it is best kept in a group of at least six, and it can be spawned in a similar way to other Corydoras.

Boulenger's featherfin tetra, Bryconaethiops boulengeri, is a large alestid characin from the Congo river basin and Lake Tanganyika. Rarely imported, it is a peaceful shoaling species for a community of larger fish, and is farmed commercially for food in its native countries. It grows to 250 mm SL.

The slender tail hap, Buccochromis lepturus, is a large cichlid endemic to Lake Malawi, also known as the green lepturus. Adults live in deeper water throughout the lake, though juveniles can be seen in quite shallow water around the shorelines. Its pelagic nature makes it difficult to catch for export, so it is rarely seen for sale. It grows to 400 mm SL, and small fish will end up on the menu.

The stripeback hap, Buccochromis nototaenia, is a predatory cichlid endemic to Lake Malawi. It hunts juveniles of other species over sandy substrates just off the shoreline, often driving them into shallower water. It is rarely seen in the trade because it retreats at great speed into deeper water at the first sign of threat, which makes it hard to collect.

Caecomastacembelus albomaculatus is a spiny eel endemic to Lake Tanganyika, where it inhabits rocky areas around the shoreline. Rarely seen in the hobby, it suits a Tanganyikan community of species too large to be considered food, and its hard, alkaline water requirements rule out most other freshwater tanks. The stiffened dorsal rays that give spiny eels their name mean care is needed when handling it.

Caecomastacembelus plagiostomus is a spiny eel endemic to Lake Tanganyika, found in shallow water over rocky areas around the shoreline. Very rarely seen in the hobby, it suits a Tanganyikan community of species too large to be considered food and is somewhat territorial with conspecifics. It grows to 300 mm SL, and its stiffened dorsal rays call for care when handling it.

The big-eyed mouthbrooder, Callochromis macrops, is a sand-sifting cichlid endemic to Lake Tanganyika, found in the southern part of the lake. It lives over shallow sandy bottoms near rocks, taking in mouthfuls of sand and sifting out invertebrates through the gills. Several geographical colour forms exist and should not be kept together, as they hybridise freely. Males are particularly belligerent towards one another in captivity, so a small tank suits one male with several females.

The humphead perchlet, Chanda pulcinella, is a freshwater ambassid endemic to Myanmar, where it inhabits large, fast-flowing, clear streams. Described in 2003, it takes its name from the scaleless hump on its head, formed from an extension of the spine and apparently smaller in females. Artificially dyed specimens have reached the market and should be avoided, since the process is cruel and usually shortens the fish's life considerably.

Chanda siamensis is a small glass fish from Thailand, Laos, Cambodia, Vietnam, Malaysia, Singapore and Indonesia. An occasional import, it is sometimes sold as C. ranga, the Indian glass fish, but lacks patterning behind the eye and has a more elongate body. C. siamensis inhabits lowland rivers and flooded fields and is exclusively a freshwater fish, so it should never be kept under brackish conditions.

The long-nosed skunk cory, Corydoras narcissus, is an armoured catfish that appears to be endemic to the Rio Purus in Brazil. It lives alongside Brochis arcuata and looks very similar at first glance, but has an elongated snout where that of B. arcuata is much more rounded. Large for a Corydoras at around 75 mm SL, it does best with some water flow in the tank.

The long-nosed smudge spot cory, Corydoras ourastigma, is an armoured catfish from the Rio Purus basin in Brazil. It can be confused with Gastrodermus guapore, Hoplisoma caudimaculatum, H. simile and Brochis spectabilis, but is the only one with an obvious long snout. Its smudged caudal blotch resembles that of H. simile but is grey to black. Nothing is recorded of its habitat.

The northern longnose cory, Corydoras septentrionalis, is an armoured catfish from the Rio Orinoco in Venezuela and possibly Colombia. It superficially resembles C. simulatus and C. amapaensis. C. amapaensis has a clear caudal fin, where this species has a noticeably barred one. It is found in main river channels and tributaries.

The ocellated bushfish, Ctenopoma muriei, is one of the smallest members of its genus, recorded from Egypt and Sudan south to Tanzania and Zambia. It lives in sluggish or still waters such as pools, lagoons and swamps, many of them low in dissolved oxygen. Rarely seen in the trade, it will eat only the tiniest fish and suits an African community with Alestiid tetras, dwarf cichlids and small Mochokid catfish.

The featherfin cichlid, Cyathopharynx furcifer, is a maternal mouthbrooder endemic to Lake Tanganyika, where it lives over scattered rocks and sand. Highly sought after in the hobby but fairly delicate, it needs a lot of space and the highest water quality, and males develop full adult colour only at around 4 inches. Males dig spawning craters up to 60 cm across. The colour forms of the two Cyathopharynx species should not be kept together, as they can hybridise.

The dogtooth cichlid, Cynotilapia afra, is a Mbuna endemic to Lake Malawi, found around the rocky shoreline. It is easily confused with some Pseudotropheus but has unicuspid teeth, and its black flank bars continue into the dorsal fin. The many colour forms should not be mixed, as they interbreed. Belligerent and very aggressive towards its own species, it is one of the hardier Mbuna and a good choice for the newcomer to these fish.

The Malawi blue dolphin, Cyrtocara moorii, is a large, peaceful cichlid endemic to Lake Malawi, found mainly over shallow sandy areas. Formerly named Haplochromis moorii, it shoals in nature and follows substrate-sifting species such as Fossorochromis rostratus to feed on morsels stirred up from the sand. Males reach at least 25 cm, and it should not be kept with boisterous species such as mbuna.

The butterfly plec, Dekeyseria picta (L168), is a flattened loricariid catfish from the Rio Negro in Brazil. The Rio Orinoco fish traded as L052 is now included in the same species. Also called the chameleon plec, it changes colour to match the substrate and other surfaces and has a distinctive night-time colouration. It needs well-oxygenated water with plenty of movement.

The wrestling halfbeak, Dermogenys pusilla, is a halfbeak widespread from India and Myanmar east to Vietnam, the Philippines and Indonesia. Males fight by locking jaws, and in some of its native countries it is used as a fighting fish with wagers placed on the outcome. Probably the halfbeak most commonly seen in the trade, it can be delicate when first imported and is flighty, so dense planting around the edges helps protect its mouthparts from the glass.

The porthole catfish, Dianema longibarbis, is a peaceful callichthyid catfish from the Amazon basin in Peru and Brazil. It is named for the row of spots running along the lateral line. All specimens in the trade are wild-caught and new imports tend to be delicate and susceptible to disease, but once acclimatised it usually proves very hardy and can live for over 10 years.

The flagtail catfish, Dianema urostriatum, is a peaceful callichthyid catfish from parts of the Brazilian Amazon basin. It lives away from the main river channels in slower creeks, tributaries, floodplain lakes and ponds. All specimens in the trade are wild-caught and new imports can be delicate, but once acclimatised it usually proves very hardy and adaptable, and suits the larger community tank.

The lyretail checkerboard cichlid, Dicrossus filamentosus, is a cichlid from the Rio Orinoco in Colombia and Venezuela and the Brazilian Rio Negro. Formerly placed in Crenicara, it shares Dicrossus with D. maculatus, which looks similar but lacks the lyretailed caudal fin. Shy by nature, it needs a well-planted, dimly lit tank with plenty of hiding places, and very soft, acidic water to breed.

The Malawi eye-biter, Dimidiochromis compressiceps, is a predatory cichlid endemic to Lake Malawi, where it is widely distributed. An ambush predator, it hides head-down among Vallisneria beds, its laterally compressed body and dark stripe from snout to tail helping to conceal it. Despite its name it mainly hunts small fish, and eye-eating happens infrequently in nature and rarely, if ever, in aquaria with well-fed specimens.

The silver distichodus, Distichodus affinis, is an active citharinid from the Lower and Central Congo basin. It develops bright red fins as it matures and some specimens a pink sheen on the underside, and these variations may indicate different species. It will eat most greenery, so it suits a tank furnished with smooth rocks and driftwood better than a planted one.

The six-banded distichodus, Distichodus sexfasciatus, is a large citharinid from Cameroon, the Democratic Republic of Congo and Tanzania. The most common Distichodus in the hobby, it is often sold for the general community tank, which its temperament and size do not suit: it reaches 75 cm, though rarely more than 40 cm in aquaria. Juveniles are orange and black striped with red fins, but much of this colour fades as the fish grows.

Descamp's strange-tooth cichlid, Ectodus descampsii, is a shy cichlid endemic to Lake Tanganyika, between Moliro and Utinta Bay. It inhabits open water over sand and is gregarious, so a group of at least eight is recommended. An undescribed fish, Ectodus sp. 'north', is sometimes imported under this name and has a smaller adult size and a black dorsal spot towards the front of the fin (in the middle in E. descampsii).

Erethistes maesotensis is a small erethistid catfish known only from a single tributary of the Salween River on the border of Myanmar and Thailand. It lives in shallow, fast-flowing water over rocks and spends much of its time buried in the substrate or hiding in caves. Its outwardly pointing pectoral-fin denticles lead many experts to place it in Hara, though it is still officially included in Erethistes.

The ropefish, Erpetoichthys calabaricus, is a nocturnal polypterid from shallow, heavily vegetated waters in Western Africa. The only member of its genus, it is closely related to Polypterus, and its divided swim bladder serves as an accessory breathing organ, so it can drown if denied atmospheric air. It grows to 90 cm and will eat tankmates it can fit in its mouth.

The red wolf fish, Erythrinus erythrinus, is a predatory erythrinid from Peru, French Guiana, Venezuela, Trinidad and Tobago and Brazil. Colour and pattern vary with collection locality, and genetic differences between populations suggest it is a species complex. A modified swim bladder lets it breathe in oxygen-deficient, stagnant water. It is very intolerant of conspecifics, often fighting them to the death, and will strike at nets and siphon tubes with its sharp teeth.

Euchilichthys guentheri is a mochokid catfish from the Democratic Republic of Congo, where it inhabits fast-flowing areas of rivers. It is very rare in the hobby. It is told apart from similar Chiloglanis species by its elliptical mouthparts and larger adult size, reaching 19 cm. It needs strong flow and well-oxygenated water, and becomes territorial with conspecifics as it matures.

Fossorochromis rostratus is a large, sand-sifting cichlid endemic to Lake Malawi, most common over shallow sandy substrates. When startled it may bury itself, and a sand substrate is essential since gravel may injure it. A very fast, active swimmer, it needs open water and should not be kept with boisterous species such as mbuna. Shoals of Cyrtocara moorii follow feeding groups in the wild to take the morsels they stir up.

The marbled lyretail, Fundulopanchax marmoratus, is a rare killifish endemic to Cameroon, found in a single area of coastal rainforest. It inhabits small streams and ponds and occurs only in permanent water, so it is not an annual species. It needs cooler temperatures than most killifishes and is best kept in a species tank.

The golden pheasant, Fundulopanchax sjoestedti, is a large killifish from Nigeria and Cameroon, reaching 12 cm, found in swampy coastal rainforest. Adult males are admired for their colouration. It was formerly classified as Aphyosemion sjoestedti, and much of the literature still uses that name. Several colour forms exist, including a smaller variety known as 'Dwarf Red'. Males are aggressive towards one another.

Fundulopanchax walkeri is a predatory killifish from the Ivory Coast and Ghana. It lives in small streams, swamps and ponds in coastal rainforest and forested savanna, and occurs as both an annual and a non-annual fish, so it can breed in permanent and temporary water. It needs cooler water than many killifishes, and will eat any fish that fits in its mouth. Some wild populations are threatened or extinct through rapid human development.

The Napo cory, Gastrodermus napoensis, long known as Corydoras napoensis, is an armoured catfish from the upper Amazon in Peru and Colombia, including the Rio Napo and Rio Nanay. It belongs to the 'elegans group' of similar species with G. elegans, G. bilineatus and G. nanus. Males show a dark marking in the upper dorsal fin, but females are much harder to identify, especially as G. napoensis and G. elegans occur together and are often sold in mixed shipments.

Nijssen's cory, Gastrodermus nijsseni, long known as Corydoras nijsseni, is an armoured catfish endemic to the Rio Negro basin in Brazil, living in acidic blackwater rivers and creeks. It was first described as a subspecies of G. elegans, and its rounded snout recalls that species, though its colour pattern is closer to Hoplisoma adolfoi. It suits a Rio Negro biotope or other softwater community.

The pygmy cory, Gastrodermus pygmaeus, long known as Corydoras pygmaeus, is one of a handful of tiny Corydoras species and appears to be endemic to the Rio Madeira basin, Brazil. Unlike most of its congeners it swims in midwater. It is most often confused with G. hastatus, which has a dark diamond-shaped spot at the caudal peduncle, where G. pygmaeus has a dark stripe along the entire lateral line. Easily intimidated by larger tankmates, it is best kept in a group of at least six with other tiny species.

Gastromyzon sp. 'SK04' is an undescribed hillstream loach from South Kalimantan province, Indonesian Borneo. Based on colour pattern it appears similar to members of the G. lepidogaster group, which also includes G. psiloetron. It has occasionally been maintained by private collectors, and like its congeners it needs clean, well-oxygenated water with strong flow.

The metallic girardinus, Girardinus metallicus, is a small livebearer from Cuba. It lives in streams, ponds and ditches where the water is commonly stagnant and often brackish. Introduced to the aquarium trade in the early 20th century, it disappeared soon after and reappeared in a Berlin zoo in 1965. Breeding is very easy provided soft, acidic water is avoided.

The red rainbowfish, Glossolepis incisus, is a rainbowfish from the Lake Sentani region of northern New Guinea, Indonesia. Also known as the salmon-red or New Guinea rainbowfish, it is usually found in shoals around heavily vegetated areas. Mass-bred fish have far less colour than wild ones. It is quite skittish and does far better in a shoal of at least 6-8.

The Lake Wanam rainbowfish, Glossolepis wanamensis, is a rainbowfish endemic to Lake Wanam in Papua New Guinea. It is now considered critically endangered, a decline thought to result from introduced tilapia, Gambusia and carp and a big rise in the number of people living around the lake. A captive breeding programme has been set up, but it has been argued that most fish in the hobby are contaminated by cross-breeding with G. multisquamata.

Gnathochromis permaxillaris is a deep-water cichlid endemic to Lake Tanganyika, recorded foraging at depths of up to 200 metres. The upper lip of adults is extended to extraordinary proportions, so the mouth faces downwards when opened, and the fish uses it to sift invertebrates from the sand. It is rare in the trade because it is difficult to collect in numbers, it is sensitive to deteriorating water quality, and the colour morphs should not be mixed as they may hybridise.

The elephantnose fish, Gnathonemus petersii, is a mormyrid with a vast African range, recorded in ten countries from Mali and Benin to Zambia. It uses its 'trunk' to find food hidden in the substrate, so it needs a soft substrate, and it needs dim lighting. Like other mormyrids it produces a weak electric field that it uses to navigate, hunt and communicate. It is very sensitive to deteriorating water conditions and to many medications, including salt.

The violet goby, Gobioides broussonnetii, is an estuarine goby from the southern USA, Central America, the Caribbean and northeastern South America. Also sold as the dragon or Peruvian goby, it grows very large (to 62.5 cm), has specialised feeding requirements and needs brackish water, as it does not survive for long in freshwater. The smaller, riverine G. peruanus is often imported under its name and is told apart by its smaller adult size and thicker, more purple body.

The aba aba, Gymnarchus niloticus, is a large predatory fish from much of the northern half of Africa, and the only species in its genus. An extended dorsal fin gives it the alternative name upside-down knifefish, although it is more closely related to the mormyrids, and it uses a weak electrical discharge to navigate and communicate. Growing to 165 cm and extremely aggressive, it is simply not suited to the home aquarium in any respect.

The silver tetra, Gymnocorymbus bondi, is a characid from the Rio Orinoco basin in Colombia and Venezuela. It inhabits small tributaries, streams and creeks. Juveniles have reddish unpaired fins that fade as they mature, and the fairly bland adults are not often seen in the hobby. Peaceful and hardy, it is sometimes labelled G. socolofi, a name now considered a junior synonym of G. bondi.

The black widow tetra, Gymnocorymbus ternetzi, is a characid from the Rio Paraguay and Guaporé basins in Brazil, Bolivia and Argentina. All the fish in the trade are captive bred and unfussy about water chemistry and diet. The intense black of juveniles fades as they grow. Long-finned and 'golden' (leucistic) forms exist, the latter often sold as the 'white skirt tetra', and artificially dyed fish also turn up, a stressful process that often shortens their lifespan considerably.

The banded knifefish, Gymnotus carapo, is a gymnotid knifefish recorded across Central and South America, from Mexico to Argentina. Several species once considered G. carapo have been described since 1994, and its massive natural range will likely turn out to be far more restricted. It uses a weak electric field to navigate and communicate, and a modified swimbladder acts as an accessory breathing organ. It grows to 60 cm and is sensitive to many medications, particularly copper.

Haplochromis latifasciatus is a cichlid found only in Lake Kyoga and the adjacent Lake Nawampasa, satellite lakes north of Lake Victoria in Uganda. Critically endangered in nature and possibly extinct in Lake Kyoga, it is quite easily bred in aquaria. It is often sold under the invalid name Astatotilapia latifasciata, or as Haplochromis sp. 'zebra obliquidens' or H. obliquidens, a Victorian species from a different lake. A maternal mouthbrooder, it must not be kept with Victorian Mbipi as they may hybridise.

The Asian stone catfish, Hara jerdoni, is a tiny sisorid catfish from India and Bangladesh, found in slow-moving streams and small rivers. It grows to around 30 mm SL and is told apart from others in the genus by its elongated pectoral spines. It and its congeners also go by the name moth catfish, after their patterning and shape when viewed from above. Very peaceful, it prefers soft substrates and is outcompeted by active bottom-dwelling species.

The silvertip tetra, Hasemania nana, is a characid from the Rio São Francisco basin in Brazil. It inhabits creeks and tributaries away from the main river channels. Hasemania is one of the few characid genera whose members lack an adipose fin. All the fish in the trade are captive bred and unfussy about water chemistry and diet, and it is sometimes sold as the 'copper tetra'.

The black-top mouse catfish, Hassar orestis, is a doradid catfish recorded in Ecuador, Colombia, Venezuela, Guyana, Peru and Brazil. It can be delicate when first imported, and fish without a rounded belly or with sunken eyes are emaciated and seldom survive long. It resembles Nemadoras leporhinus, which has longer first fin rays and a clear dorsal fin with a dark patch at the base. Like other doradids it produces audible sounds, and its pectoral spines tangle easily in nets.

L106, Hemiancistrus guahiborum, is a suckermouth catfish known only from the Rio Orinoco drainage in Venezuela. Also known as the spotted orange seam plec, it lives amongst rocks in flowing water and needs well-oxygenated water with some current. Described in 2005, it may be the same species as the undescribed L122, although the flatter profile of L122 suggests the two are distinct.

The blue phantom plec (L128) is a suckermouth catfish known only from the northern Rio Orinoco drainage in Venezuela. Its identity is unresolved. It closely resembles Hemiancistrus subviridis, the green phantom plec (L200), and the colour of the two grades from one into the other along the same river system, suggesting colour forms of one species, but this awaits scientific confirmation. Newly imported fish can be delicate, and emaciated fish with sunken eyes do not often survive for long.

The jewel cichlid, Hemichromis bimaculatus, is a cichlid from Africa's western coast, between southern Guinea and central Liberia. Regularly seen in the trade and often sold as a community fish, it is not recommended for the beginner or the general community tank, and it becomes very aggressive when spawning. It can be told from H. lifalili by a third black spot, on the caudal peduncle.

The blood-red jewel cichlid, Hemichromis lifalili, is a cichlid endemic to the Democratic Republic of Congo. Often confused with H. bimaculatus, it has two black spots on the flanks against that species' three, and its round midlateral marking sits above the lateral line, unlike the oval one of the red form of H. guttatus. It becomes very aggressive when spawning but is fairly placid otherwise, and is not a particularly good species for the community tank or for newcomers to cichlids.

The barrigona tetra, Hemigrammus barrigonae, is a small characin from the Rio Meta and Orinoco basins in Colombia and Venezuela. It inhabits slow-moving rivers and tributaries. Not a common species in the hobby, it occasionally shows up as a contaminant among imports of more popular species. Like all Hemigrammus, its taxonomic status is Incertae Sedis, and most experts agree the genus needs a full revision.

The dash-dot tetra, Hemigrammus belottii, is a small characin from the Rio Solimões, Negro and Maroni basins in Brazil and French Guiana. It is not common in the trade, and most specimens come in as contaminants among batches of more popular species. Like all Hemigrammus, its taxonomic status is Incertae Sedis, and most experts agree the genus needs a full revision.

Boesman's tetra, Hemigrammus boesemani, is a small characin officially recorded from Suriname, French Guiana and Peru. It favours sluggish and still waters. Very rare in the hobby, it was once considered a subspecies of H. micropterus. The recorded range suggests it has been misidentified in at least one of these countries or occurs in others as well.

The shiny copper tetra, Hemigrammus cupreus, is a small characin known only from the Rio Solimões in Brazil. It lives in the turbid white water of the river itself and in flooded habitats including the lakes known as várzeas, where conditions are far less acidic than in blackwater. Not common in the hobby, it occasionally shows up as a contaminant among imports of more popular species.

The glowlight tetra, Hemigrammus erythrozonus, is a small characin known only from the Rio Essequibo in Guyana. Hardy and inexpensive, it is one of the best choices for a newcomer to fishkeeping. All fish in the trade are mass-bred on commercial farms, and a selectively-bred albino form is also sold. In nature it lives in forested tributaries with tannin-stained, often highly acidic water, and it is more colourful in acidic conditions.

The January tetra, Hemigrammus hyanuary, is a small characin from the Amazon basin in Peru and Brazil. Also known as the costello or green neon tetra, it resembles an elongated head and tail light tetra, H. ocellifer, and is occasionally confused with it. The type specimen came from Lake Hyanuary near Manaus. It inhabits slow-moving rivers, tributaries and floodplain lakes and tends to lose colour in alkaline water.

Hemigrammus levis is a small characin native to the Brazilian Amazon, found in slow-moving rivers, tributaries and floodplain lakes. A rather rare fish in the UK hobby, it occasionally shows up as a contaminant among imports of more popular species. Like all Hemigrammus, its taxonomic status is Incertae Sedis, and most experts agree the genus needs a full revision.

The golden tetra, Hemigrammus rodwayi, is a small characin native to Guyana, Suriname, French Guiana, Peru and Brazil. Its normal colour is a rather dull silvery grey. In some areas wild fish react to a trematode parasite with metallic gold deposits of guanin in the skin, and these were once described as a separate species, H. armstrongi. Captive-bred fish are not exposed to the parasite, so most 'golden tetras' on sale lack the gold colour.

The red-base tetra, Hemigrammus stictus, is a small characin from Venezuela, Guyana and Brazil. It inhabits slow-moving rivers, tributaries and floodplain lakes. Not often seen for sale, it occasionally shows up as a contaminant among imports of more popular species. Like all Hemigrammus, its taxonomic status is Incertae Sedis, and most experts agree the genus needs a full revision.

The broken-line tetra, Hemigrammus ulreyi, is a small characin known only from the Brazilian part of the Rio Paraguay basin. Other species are frequently misidentified as H. ulreyi, and the true fish is quite scarce in the hobby. It inhabits slow-moving rivers and tributaries. Like all Hemigrammus, its taxonomic status is Incertae Sedis, and most experts agree the genus needs a full revision.

The featherfin tetra, Hemigrammus unilineatus, is a small characin widespread across northern South America, from Venezuela to Peru and Brazil. Despite its abundance in nature it is not commonly seen in the hobby, and usually turns up only as a contaminant among imports of other species. A very peaceful shoaling fish, it inhabits slow-moving rivers, tributaries, oxbow lakes and ditches, some clear and others murky with sediment.

Hemigrammus vorderwinkleri is a small tetra known only from the Rio Negro in Brazil, where it inhabits blackwater rivers and tributaries. It is most likely to be seen as a contaminant among imports of other species. A very peaceful shoaling fish growing to around 40 mm SL, it suits a blackwater biotope or a heavily planted tank, since fish on sale will almost certainly be wild caught.

The Pinocchio whiptail catfish, Hemiodontichthys acipenserinus, is a loricariid from Guyana, French Guiana, Peru, Bolivia and Brazil. Also known as the knob nosed whiptail, it is hard to confuse with any other Loricariid thanks to its diamond shape seen from above and the enlarged tip of its rostrum. Imports often arrive weak from oxygen deprivation and early losses are high, but once acclimatised it is quite easy to keep over the soft sand in which it partially buries itself.

Hemiodus argenteus is a shoaling hemiodontid characin from Venezuela, Guyana, Suriname and Brazil, where it inhabits floodplain rivers and lakes. Like its congeners it can be very skittish when first introduced but usually settles over time, especially in a large group. Very active and growing to around 235 mm SL, it needs a large tank with a well-fitting cover, as it can leap surprising distances.

Hemiodus atranalis is a shoaling hemiodontid characin from Guyana, Peru and Brazil, found in floodplain rivers and lakes. Its reported maximum size is only 90 mm, though it probably grows bigger than this. Very active and skittish when first introduced, it usually settles in a large group, and the tank needs a well-fitting cover since it can leap surprising distances.

The slender hemiodus, Hemiodus gracilis, is a shoaling characin from Venezuela and Brazil, found in floodplain rivers and lakes. Probably the most often seen member of the genus in the hobby, it is sometimes sold as the red or red-tailed hemiodus. Very active and nervous when first introduced, it settles best in a large group in a spacious tank with a well-fitting cover.

Hemiodus orthonops is a large, shoaling hemiodontid characin from Brazil, Paraguay and Argentina, where it inhabits floodplain rivers and lakes. Growing to around 250 mm SL and very active, it needs a tank of at least 120 cm with a well-fitting cover. Like its congeners it can be nervous when first introduced but usually settles over time, especially in a large group.

Hemiodus ternetzi is a shoaling hemiodontid characin known only from the Rio Tocantins basin in Brazil. It can be identified by its black lateral stripe, which extends to behind the eye, and a dorsal fin with no pigmentation. Like other Hemiodus it can be skittish when first introduced but usually settles, especially in a large group.

Hemiodus unimaculatus is a large, shoaling hemiodontid characin from Guyana, Suriname, French Guiana and Brazil. It inhabits floodplain lakes and fast-moving parts of rivers and grows to around 215 mm SL. Somewhat flighty, it needs a spacious, well-covered tank and a large group to settle, and in nature it is known to spawn during the wet season.

The moustache catfish, Hemisynodontis membranaceus, is a large mochokid widespread in Africa, from Egypt and Sudan to Senegal and Nigeria. Its 'moustache' is a membrane along the maxillary barbels. It feeds mainly on plankton, filtered through its many gill rakers, and often feeds at the surface upside down. Often sold as a spotted juvenile, it can reach 50 cm and becomes territorial with conspecifics as it matures.

The African pike characin, Hepsetus odoe, is a predatory characin widespread in Africa, from Senegal and Guinea to Angola, Namibia and Zimbabwe. The only species in its genus, it is an ambush predator with a fearsome set of teeth that superficially resembles the European pike. Juveniles appear in the trade, but it reaches 70 cm in nature and is strictly for the specialist with a very large aquarium.

The pearlscale cichlid, Herichthys carpintis, is a large cichlid from northern Mexico, found in lagoons around the mouth of the Panuco drainage. It is often mislabelled as the Texas or green Texas cichlid, though the Texas cichlid is a different species, H. cyanoguttatus. Not difficult to keep or breed, it digs, can be territorial and sometimes downright aggressive, and males may turn on females when spawning.

Herichthys pearsei is a large, almost exclusively vegetarian cichlid from the coastal waters of eastern Mexico and Guatemala. Males reach around 42.5 cm and females around 35 cm, so a fully grown male or pair needs a tank of around 240 cm, and any plants will be eaten. For its size it is quite placid, and suits a community of bigger fish that share its need for hard, alkaline water.

The severum, Heros efasciatus, is a cichlid from the Amazon main channel and the Rio Solimoes, also recorded from the Rio Xingu. One of the most popular and readily available cichlids in the hobby, it is sold in the standard green form and in gold. Many buyers do not realise it grows fairly large, often 20 to 25 cm in aquaria, and it needs a tank of at least 120 cm. Outside spawning it is fairly mild-mannered for its size.

The spotted severum, Heros notatus, is a cichlid endemic to the Rio Negro basin in Brazil, where it inhabits blackwater rivers and tributaries. Rarely seen, it is occasionally offered by specialist cichlid or South American dealers. Not a particularly aggressive species, though males may squabble with conspecifics, it suits a larger cichlid community, and much smaller fish will almost certainly be eaten.

The rainbow cichlid, Herotilapia multispinosa, is a Central American cichlid from eastern Honduras and throughout Nicaragua and Costa Rica. Peaceful by Central American standards, it suits fishkeepers who do not want the more aggressive species, and can live with tetras, barbs and smaller peaceful cichlids. In nature it inhabits turbid lakes, swamps and marshes with soft, muddy substrates, and in the aquarium it typically reaches around 10 cm.

The vundu, Heterobranchus longifilis, is a clariid catfish widespread throughout Africa and one of the largest freshwater fishes on the continent. Growing to 150 cm, it is highly predatory, must be kept alone, and suits only public aquaria or a hobbyist able to house it properly. Its very long adipose fin separates it from similar members of the genus.

The liver catfish, Heteropneustes fossilis, is a catfish from Iran, Pakistan, India, Nepal, Sri Lanka, Bangladesh, Myanmar and the Andaman Islands. Also known as the stinging or fossil catfish, it carries venom sacs at the base of the pectoral spines and its sting is very painful, so it is not recommended for the inexperienced. Exceptionally hardy and long-lived, it can breathe atmospheric air to a certain extent and survives in sluggish, oxygen-deficient swamps and ditches.

The head-and-tail light tetra, Holopristis ocellifera, is a small characin from Guyana, Suriname, French Guiana, Peru and Brazil. Also known as the beacon tetra, it is hardy, inexpensive and one of the best choices for a newcomer to fishkeeping. Wild fish are rarely offered, since it is commercially bred in huge numbers for the trade, and a selectively bred albino form is also available.

The pretty tetra, Holopristis pulchra, is a small characin endemic to the Upper Amazon in Peru, found in slow-moving tributaries under forest cover. Also known as the garnet or black wedge tetra, it is hardy, inexpensive and a good choice for the beginner. The vast majority on sale in the UK come from commercial farms in Eastern Europe, and it does well in most general community tanks.

Hoplisoma loretoense, long known as Corydoras loretoensis, is an armoured catfish from the upper Amazon in Peru, growing to around 50 mm SL. The profile singles out its very long dorsal spine. Nothing is recorded of its habitat.

Hoplisoma loxozonum, long known as Corydoras loxozonus, is an armoured catfish from the Rio Meta basin in Colombia, also referred to by its C-number, C082. Its habitat in the wild is unknown. It prefers slightly lower temperatures than many Corydoras, which matters when choosing tankmates.

The spotted cory, Hoplisoma melanistium, long known as Corydoras melanistius, is an armoured catfish from coastal rivers and tributaries of Guyana, Suriname and French Guiana. It can be told from the similar Brochis delphax by its 12-13 dorsal-fin rays, against usually 7 in B. delphax. Two subspecies once assigned to it are now H. brevirostre and B. ambiacus.

Natterer's cory, Hoplisoma nattereri, long known as Corydoras nattereri, is an armoured catfish from coastal zones of southern Brazil between Espírito Santo and Paraná. Also known as the blue cory, it needs slightly cool conditions, in which many commonly available fish fail to thrive.

The flag-tailed panda cory, Hoplisoma oiapoquense, long known as Corydoras oiapoquensis, is an armoured catfish from the upper Rio Oyapock in French Guiana and Brazil. It lives alongside the near-identical Brochis condiscipulus, and the two are often found shoaling together. The only external differences seem to be the longer snout and wider distribution in the Oyapock of B. condiscipulus.

The pepper cory, Hoplisoma paleatum, long known as Corydoras paleatus, is an armoured catfish from southern Brazil, Uruguay, Paraguay and Argentina. Along with the bronze cory it is one of the most commonly found corys in the hobby. Most fish on sale are captive bred for the trade, and wild-caught specimens are much more vividly coloured. In nature it lives in rivers, tributaries and standing waters including pools and small lakes.

The panda cory, Hoplisoma panda, long known as Corydoras panda, is an armoured catfish from the upper Amazon in Peru, named for dark and light markings that recall the giant panda. Wildly expensive when first imported in the late 1970s, it is now mass-produced, and virtually all fish in the trade are farmed. Wild fish live in clear and blackwater streams that cool to around 19 °C when Andean meltwater arrives.

Sterba's cory, Hoplisoma sterbai, long known as Corydoras sterbai, is a peaceful armoured catfish from Bolivia and Brazil, marked with light spots on a dark head. Almost all fish in the trade are produced commercially on farms. The head pattern separates it from the similar Brochis haraldschultzi, in which the markings are dark on a light background, and it is generally considered one of the easiest Corydoras to spawn.

The black collared catfish, Horabagrus nigricollaris, is a bagrid catfish endemic to the Chalakudy River in Kerala, south-western India. The rarer of the two species in the genus in the hobby, it resembles the much larger H. brachysoma. Both are usually sold as juveniles, and in this species the black shoulder marking extends up and over the top of the body, giving the collar that names it.

Horadandia atukorali is a miniature cyprinid from Sri Lanka and southern India, where it is restricted to Kerala, Tamil Nadu and Puducherry. Its small adult size evolved through miniaturisation, and it shows a preference for sluggish and still waters such as rice paddies, swamps and weedy ponds. Very peaceful but timid, it does best alone or with other diminutive species in a densely-planted tank.

The shadow catfish, Hyalobagrus flavus, is a small bagrid catfish from the Batang Hari drainage in Sumatra and the Mentaya basin in Borneo. For many years it has been imported as Pelteobagrus ornatus. Unlike most catfish it is diurnal and spends much of its time swimming in shoals in midwater, and it suits a peaceful community with soft, acidic water.

The African tiger fish, Hydrocynus vittatus, is a large predatory alestid found throughout Africa, from Egypt to South Africa. A voracious piscivore with dagger-shaped, interlocking teeth, it hunts in large shoals in the wild and is a popular game fish. Small specimens show up quite frequently in dealers' tanks, but even an aquarium of 300 by 90 cm is too small for an adult.

The spotted cochliodon (L050), Hypostomus cf. cochliodon, is an undescribed suckermouth catfish of the Hypostomus cochliodon complex. Like other members of the group it develops a hump-backed profile and spoon-shaped teeth, and eats wood. Its exact distribution is unknown. It grows to around 230 mm SL and is non-territorial enough to keep in a group or with other peaceful loricariids.

LDA10, Hypostomus mutucae, is a small suckermouth catfish from Mato Grosso, Brazil, with its type specimen collected in the Rio Mutuca. It grows to around 75 mm and is peaceful, and it inhabits flowing, highly oxygenated water over sand scattered with rocks. It is often confused with LDA09 but has smaller spots on the head, where LDA09 has larger spots of uniform size all over.

Hypostomus plecostomoides (LDA42, LDA38) is a wood-eating suckermouth catfish from the Rio Orinoco drainage in Colombia and Venezuela. A member of the Hypostomus cochliodon complex, it has a hump-backed profile and spoon-shaped teeth. It is very difficult to tell from H. hondae, H. pagei and H. taphorni, and collection locality is often the best guide.

The chocolate cichlid, Hypselecara temporalis, is a large cichlid from Peru, Colombia, Venezuela and Brazil. It most often inhabits silt-laden, slow-flowing rivers, and has been collected in the Ucayali, Amazonas, Solimões, Amapá and Oyapock. Although it reaches 30 cm, it is quite a placid species and can be kept in a community of large fish in a suitably-sized tank.

Jerdon's carp, Hypselobarbus jerdoni, is a large cyprinid endemic to India, recorded from Maharashtra, Karnataka, Kerala and Tamil Nadu. A riverine fish of clear, well-oxygenated, running water, it can reach 46 cm and is very rarely encountered in the trade. Very active and a vigorous feeder, it needs a tank of 240 ∗ 120 ∗ 120 cm or more for a group of adults, and many Indian authors consider it endangered.

The Nicaragua cichlid, Hypsophrys nicaraguensis, is a Central American cichlid from Nicaragua and Costa Rica, found in lakes and slow-moving rivers. Also known as the spilotum or moga, it exists in several colour forms depending on collection locality, and has been hybridised with the convict cichlid, Archocentrus nigrofasciatus. Relatively peaceful for its size but territorial, it is best kept as a mated pair and spawns in caves.

The goldbreast goodeid, Ilyodon furcidens, is a livebearer from Jalisco and Colima in Mexico, found in fast-flowing streams and small rivers. Also called the goldbreast splitfin, it is named for its fork-shaped teeth. Like other goodeids it nourishes its developing young through a trophotaenia, and females must be mated separately for each brood. A peaceful fish, it suits a community whose other species can cope with the lower temperatures it needs.

The purple emperor tetra, Inpaichthys kerri, is a small characin from the Rio Aripuanã and upper Rio Madeira basins in Brazil. Also sold as the 'blue emperor', 'regal' or 'royal' tetra, it is sometimes confused with the emperor tetra, Nematobrycon palmeri, but can be told apart by its adipose fin (absent in Nematobrycon). It lives in sluggish, tannin-stained forest tributaries and has been spawned regularly in the hobby.

The rusty cichlid, Iodotropheus sprengerae, is a dwarf mbuna endemic to Lake Malawi, around the islands of Boadzulu, Chinyankwazi and Chinyamwezi. One of the least aggressive and smallest mbuna in the hobby, it is easily outcompeted by bigger species and can be kept in smaller tanks. It is sometimes confused with certain populations of Labidochromis vellicans, and as a polygamous maternal mouthbrooder is easily bred.

The brown julie, Julidochromis dickfeldi, is a cave-spawning cichlid endemic to Lake Tanganyika. It inhabits shallow rocky shorelines in the southwest of the lake, between Kapampa and Ndole. There is some speculation over whether it belongs in Julidochromis, since it has a pointed snout, blue edging to the dorsal and anal fins and very dark horizontal stripes. It is aggressive towards conspecifics and should be kept as a pair.

Regan's julie, Julidochromis regani, is the largest species of Julie, a cichlid endemic to Lake Tanganyika. It reaches 30 cm but rarely grows beyond 15 cm in aquaria, and is the least aggressive member of the genus. Less of a rock dweller than its congeners, it is more often found over sand with scattered rocks, though it still spawns in rocky caves. It may also be seen for sale as the striped or convict julie.

The blue tetra, Knodus borki, is a small characid from Colombia and Brazil, found in rivers, streams and tributaries. Its colour is often so intense that many who first see it for sale assume it has been artificially coloured, though it will not develop its best colours in sparse surroundings. It may nip the fins of conspecifics and long-finned fishes, which a group of 8-10 in a larger tank helps to limit.

Kottelatlimia katik is a miniature cobitid loach from Johor in Peninsular Malaysia and the Batang Hari drainage of Sumatra, reaching 13.5 mm SL. It is considered paedomorphic, keeping juvenile features such as long fins and long nasal barbels into adulthood. It lives in small forest streams associated with blackwater peat swamps, often in leaf litter, and needs a soft sandy substrate and spotless water.

Fuelleborn's cichlid, Labeotropheus fuelleborni, is an mbuna endemic to Lake Malawi, found in turbulent shallow water around rocky shorelines. An overhanging snout and chisel-shaped teeth let it graze algae from rocks other species cannot reach. It occurs in many colour forms, including orange and orange blotch females, and forms should not be mixed as they may hybridise. It is aggressive and territorial and should not be kept with peacocks or utaka.

Trewavas' cichlid, Labeotropheus trewavasae, is an mbuna endemic to Lake Malawi, living around rocky shorelines and islands with heavy algal growth. It is told from the similar L. fuelleborni by its more slender body and smaller adult size, and has been recorded at greater depths. Over 40 colour forms are recorded in nature, and they should not be mixed in aquaria as they may hybridise. It is very aggressive towards its own kind.

Labidochromis caeruleus is a relatively peaceful mbuna from the northern part of Lake Malawi, best known in the hobby for its 'electric yellow' morph. That morph is one of the rarer forms in nature, where the blue and white variety is more widespread, and most fish on sale are tank-bred. It lives among rocks and in beds of Vallisneria. It was originally imported as L. tanganyicae, and should not be mixed with other forms or Labidochromis species as they may hybridise.

Labidochromis sp. 'perlmutt' is an mbuna endemic to Lake Malawi, known from Higga Reef and Mbamba Bay, where it lives in deep rocky zones. Discovered in 1995, it takes its name from the German for 'mother of pearl', after the pearly white colouration of adults, and is also sold as Labidochromis sp. 'yellow bar'. The Mbamba Bay Island population closely resembles L. caeruleus and the two hybridise freely, so they should not be kept together.

Lamontichthys llanero is a suckermouth catfish from the Orinoco basin in Venezuela. It lives among rocky substrates and driftwood snags in shallow, flowing water, and needs well-oxygenated water with plenty of movement. Unaggressive and peaceful with conspecifics, it is rarely seen in the hobby.

The Congo lamprologus, Lamprologus congoensis, is a cichlid from fast-moving stretches of the Congo River in the Republic of Congo and DR Congo. It resembles Steatocranus species in shape and lifestyle, with a streamlined body, strong pectoral fins and a much-reduced swimbladder that makes it less buoyant. Aggressive and territorial, it should not be kept with other cichlids. It spawns polygamously in caves, and males develop a prominent nuchal hump.

Lasiancistrus tentaculatus (L092, L194) is a wood-eating suckermouth catfish from Colombia and Venezuela. The only primarily wood-eating Lasiancistrus, it will not do well without wood as a food source, and lives among driftwood snags in rivers. Mature males develop a few Ancistrus-like tentacles around the mouth, the only species in the genus to do so. Sunken eyes and a belly that is not rounded are classic signs of emaciation in newly imported fish.

The marbled pim, Leiarius longibarbis, is a large pimelodid catfish from the Rio Orinoco, Rio Essequibo and Amazon basins. It grows to around 80 cm and can live for well over 20 years, and whether it should be considered an aquarium subject at all is debatable. Much of the literature still lists it as L. marmoratus, a name treated as a junior synonym since a reclassification in 2003.

The sailfin pim, Leiarius pictus, is a large pimelodid catfish from the Rio Orinoco basin in Colombia and Venezuela and the Amazon in Peru and Brazil. Also known as the painted, saddle or marbled sailfin catfish, it reaches around 60 cm and can live for well over 20 years. Juveniles are often sold without adequate information on their long-term care, and a fully-grown fish needs a tank in the region of 240 by 90 by 120 cm.