Cyprinodontoid Toothcarps

This species was introduced into the aquarium trade in the early 20th century but disappeared soon after. It subsequently reappeared in a Berlin zoo in 1965 and has been available from specialist breeders ever since. It occasionally appears for sale in aquatic shops....

Endler's Livebearer was actually discovered in 1937 by Franklyn F. Bond before being rediscovered by John Endler in 1975 in Laguna de Patos, Cumana, northeastern Venezuela. It was found coexisting, but not interbreeding with, a wild form of P. reticulata. Both species are native to this area of Venezuela, but P. reticulata was much less common in areas where P. wingei was thriving. This is thought to be partially related to habitat type, as guppies are usually found in colder, running water...

An incredibly hardy and adaptable species that is not so popular in the hobby as it once was, probably due to its often aggressive nature. As with other goodeids, there is less of a size difference between the sexes than in many other livebearers. This is thought to be related to the relatively primitive structure of the andropodium, as the fish tend to choose mates that are of similar size so that the sex organs are synchronised. Goodeids are unique among livebearers in that the developi...

Another massively popular aquarium fish, with dozens of selectively bred varieties available, including mickey mouse, wagtail, tuxedo, moon, blue, red, comet and hi-fin. Some of these are produced by crossbreeding with X.helleri or X. variatus. Unfortunately many commercially bred platies are not very hardy due to inbreeding and over-production and are prone to disease and premature death. Wild fish are almost never seen in the hobby. As long as the ph remains above neutral this fish is ...

Another massively popular aquarium fish, with dozens of selectively bred varieties available. Some of these are produced by crossbreeding with X.helleri or X. maculatus. Unfortunately many commercially bred platies are not very hardy due to inbreeding and over-production and are prone to disease and premature death. The wild X. variatus can be distinguished from X. maculatus by its slimmer, more elongated body shape and slightly longer dorsal fin. This last feature has been seized upon by many...

For many years G. affinis was thought to be the same species as the Eastern Mosquitofish, G. holbrooki, but has since been given distinct species status. They can be distinguished by several means. In G. holbrooki the leading ray of the males' gonopodium has a serrated edge, theusually has 7 rays and males also generally have a higher degree of dark spotting on the body than G. affinis males. Male G. affinis also lack the serrated leading ray of the gonopodium and this species usually has o...

The Iranian Plateau is home to a diverse group of Aphanius with four species already described and several awaiting description. These are among the most ancient in the genus having divereged away from a common ancestor around 20 - 24 million years ago. Among them this species is most closely related to A. sophiae from the Kor River system but can be distinguished by differences in patterning. Males of A. sophiae lack the characteristic darkcolouration seen in A. vladykovi and females possess a ...

The species name 'furcidens' is derived from the interesting fork-shaped teeth of this fish. This species may develop a cervical hump as it matures. As with other goodeids, there is less of a size difference between the sexes than in many other livebearers. This is thought to be related to the relatively primitive structure of the andropodium, as the fish tend to choose mates that are of similar size so that the sex organs are synchronised. Goodeids are unique among livebearers in t...

This species was originally classified in the genus Limia before this was made a sub-genus of Poecilia. Confusingly they have been reclassified once more into Limia, but are still referred to as members of Poecilia in much of the available literature. L. melanogaster is endemic to Jamaica. It is not often seen for sale in the hobby....

The wild fish can exhibit several different types of patterning. P. latipinna has been selectively bred into many different colour morphs for the aquarium trade, and has also been crossbred with other molly species, particularly P. sphenops. They will also interbreed readily in the aquarium and in order to avoid this we suggest keeping only one species of molly per tank. There also exists a (in our opinion) grotesque 'balloon' variety of this fish in which the body is malformed and rou...

One of the most popular aquarium fish in the world, the guppy is instantly recognisable to most people. There are many aquarium bred varieties of this species available, most have elongated finnage and gaudy colouration. The wild form is seldom seen for sale. Unfortunately many commercially bred guppies are not very hardy due to inbreeding and over-production and are prone to disease and premature death. We therefore recommend the purchase of quality stock from breeders or society auctions. P. ...

A hugely popular aquarium fish. Many aquarium-bred colour morphs of this species are available, including the ubiquitous black molly. There are also Gold, Green, Lyretail, Silver and Dalmation varieties. Some of these are the results of P. sphenops being crossed with P. latipinnis. The 2 species will also interbreed readily in the aquarium and in order to avoid this we suggest keeping only one of them per tank. There also exists a (in our opinion) grotesque 'balloon' variety of this fi...

Another popular molly in the hobby, and another that has been selectively bred to produce several different varieties, such as albino, black, red etc. Some of these are the result of cross breeding with P.latipinna. There also exists a (in our opinion) grotesque 'balloon' variety of this fish in which the body is malformed and rounded, giving a balloon-like appearance. This condition can cause swimbladder and digestive problems and may bring about premature death. It is difficult to...

The genus Procatopus currently comprises half a dozen members (P. aberrans, P. lambertii, P. nimbaensis, P. nototaenia, P. schioetzi and P. similis), all of which are are non-annual species existing in permanent bodies of water. They are actually more closely related to the livebearing species of the subfamily Poeciliinae than the popular Aplocheilid killifish. None are particularly popular in the aquarium trade, although specialist dealers may have them available from time-to-time. Some such as...

This is an exceptionally hardy and adaptable species. It's not an especially common fish in stores, but is quite widely available in hobbyist circles. The common name arises from the row of modified, paired scales that form a keel running from the base of theto the caudal fin....

This species is not a common aquarium species but is occasionally available from specialist retailers or breeders. It was initially named Adinia multifasciata by Girard (1859) before later being redescribed as Fundulus xenicus (mispelled 'Fundnlus') by Jordan and Gilbert (1882). Body stout and trapezoidal in adults, body depth usually 2 to 3 times in standard length; scales large, fewer than 30 scales along midlateral scale row...

Also known as the mosquito fish, least killifish or dwarf top minnow, H. formosa is the smallest known livebearing fish species, and one of the smallest overall fish species in the world. It's not often seen for sale these days, although it's quite widely available in hobbyist circles. When buying these, ensure they have been identified correctly as they're sometimes confused with the much more aggressive mosquito fish of the genus Gambusia....

The eye of Anableps species is split horizontally by a band of epithelial tissue. It has two corneas, two pupils, a single, egg-shaped lens and one retina that's also split into two sections. The lens is oval and asymmetric with the upper part flattened as in the human eye and the lower section curved as in most other fishes. The upper cornea is thicker and enriched with glycogen which possibly helps to protect it from drying and UV irradiation. Two horizontal flaps of the iris are thought ...

A. anatoliae is the most widely-distributed of the Anatolian Aphanius species although like most of its congeners is not easy to come by in the hobby. You are unlikely to find it on sale in aquatic stores although it may be available via specialist breeders or associations from time-to-time. While Aphanius spp. are certainly not as colourful as some of their relatives their interesting behaviour and continuous activity make them fascinating aquarium subjects and well worth a try if you possess the de...

This species has something of a confused history having been previously been considered synonymous with both A. sophiae and A. fasciatus. Another species, A. chantrei is still listed as valid by some sources but is now known to be a junior synonym of A. danfordii. This became clear during a 1999 study in which the type specimens of A. danfordii were found to be indistinguishable from the Aphanius population living in the Sultan Swamps, the type locality of A. chantrei. You're unlikely t...

The elongated, slender body profile, angular lower jaw and reduced scalation exhibited by this little-known subspecies have seen it placed in the disused genera Anatolichthys and Kosswigichthys in the past and it's still inexplicably listed as a species of Lebias by some sources (for the record Lebias has long been considered a synonym of Cyprinodon by most authorities and an ICZN committee voted to suppress the name in favour of Aphanius as recently as 2003). You're unlikely to find i...

The elongated, slender body profile, angular lower jaw and reduced scalation exhibited by this little-known subspecies have seen it placed in the disused genera Anatolichthys and Kosswigichthys in the past. It has also been referred to, and still is in some cases, as A. transgrediens or more often A. burdurensis/burduricus. Some of these names were erected due to the differences in scalation that can be observed among the population in Lake Burdur but studies by Villwock and others revealed that...

Prior to its description this species had been considered a form of A. anatoliae and also referred to as A. sp. aff. danfordii but collections in the early part of this century motivated new studies and resulted in its elevation to full species level. Phylogenetic analyses have shown it to represent the sister group to all other Anatolian Aphanius spp. The Anatolia region represents a centre of diversity for the genus with ten endemic species described to date. These are thought to have diverged ...

A. dispar should only be considered a nominal species as demonstrated by Hrbek and Meyer (2003) who conducted an in-depth phylogenetic study covering the majority of the genus. It was found to represent a paraphyletic grouping meaning it cannot be considered to be a species following the phylogenetic species concept. A. mento, A. sirhani and especially A. ginaonis and A. richardsoni were found to be its closest surviving relatives. Hoedeman (1951) suggested that it should be moved into a separat...

Phylogenetic studies have shown this species to be most closely related to A. dispar, A. richardsoni and A. ginaonis within the genus. It probably became isolated when the Red Sea flooded the Wadi Sirhan around 13 million years ago. You 're unlikely to find it on sale in aquatic stores although it may be available via specialist breeders or associations from time-to-time. While Aphanius spp. are certainly not as colourful as some of their relatives their interesting behaviour and continuous acti...

A 2003 phylogenetic study by Hrbek and Meyer showed that in genetic terms specimens of A. fasciatus collected from different localities do not vary as much as with other members of the genus. The latter tend to exist in geographically separated populations and exhibit localised differentiation. While A. fasciatus does show certain disparities in appearance depending on locality it is thought that periodic migration events have restricted the development of genetic diversity within the species to...

Prior to its description this species was considered a geographic variant of A. iberus but the 2002 paper revealed the pair to be genetically quite distinct and also highlighted some morphological differences. It is distinguished from A. iberus by possessing 8-9 (usually 8 ) branched dorsal-fin rays (vs. 8-9, sometimes 10), 9-11 branched anal-fin rays (vs. 8-9), a deeper, more elongate body shape, noticeably shorter snout, relatively thick (vs. thin) vertical bars in males and a flank patterning consisting of a few la...

Populations of Aphanius from Spain's southern, Atlantic coastline and Algeria previously considered representative of A. iberus have now been elevated to full species status with the names A. baeticus (Doadrio, Carmona & Fernández-Delgado, 2002) and A. saourensis (Blanco, Hrbek & Doadrio, 2006), respectively. All three species look broadly similar although A. saourensis can be easily identified as the patterning in males is mottled and does not form vertical bars, while femal...

All Algerian Aphanius populations were considered to be representative of A. iberus until this species was described in 2006. It differs both morphologically and genetically from A. iberusand A. baeticus, probably diverging about 5.3 million years ago during the opening of the Straits of Gibraltar. It is most easily distinguished by the distinct mottled body patterning which in males of the other two species forms distinct vertical bars and in females dark spot-like markings. A. iberusis now k...

Restricted to a series of small habitats below the waterfall known as 'El Salto' in the upper Río Mezquital basin, Durango state, central Mexico. It was previously considered to occur throughout much of the upper Río Mezquital in both Durango and Coahuila states, but genetic analyses suggest otherwise and have resulted in taxonomic confusion (see 'Notes').

Endemic to a handful of natural springs in the Río Verde valley, San Luis Potosí state, Central Mexico. The valley is believed to have once been filled by a large lake and the relict springs are part of the elevated Río (river) Verde basin which later drains into the much larger Río Pánuco system. Much of the aquatic fauna found in the valley is endemic to the area but in many cases threatened by introduced species.

The type locality originally consisted of a single spring-fed pond located in an endorheic basin known as 'La Hediondilla' at the foot of the 'Cerro Potosí' mountain and around 1880 m AMSL. It had been modified to make it larger via an earth and rock dam, and below the pond were several distributaries running for a distance of 1-1.5 km.

This species was available in the aquarium hobby for a number of years prior to publication of the official description and was generally referred to as A. sp. 'Namak' or A. sp. 'Namak River'. It can be distinguished from other members of the genus by the following combination of characters: 10–12 anal-fin rays; 28–32 lateral line scales, 10–13 caudal peduncle scales; 8–10 gill rakers; 12–19, commonly 1...

This species is still sometimes listed as a species of Lebias by some sources although that name has long been considered a synonym of Cyprinodon by most authorities and an ICZN committee voted to suppress the name in favour of Aphanius as recently as 2003. It was known as A. persicus until late 2011 when it was reclassified due to that name being preoccupied by a Late Miocene fossil species previously referred to as Brachylebias persicus Priem 1908. This change was necessary because Gau...

Contrary to many reports, including a number of scientific papers, this species breeds in the same way as other cyprinodontids and does not dig pits or exhibit extended parental care. It's a fractional spawner with females depositing eggs on a more-or-less continuous basis when a warm temperature is maintained though ideally it should be permitted to breed on a seasonal basis in spring and late summer as it would in nature.

The hump that develops along the spine of adult males is caused by deposition of fatty tissue.

Endemic to the Río Atrato drainage in Choco and Antioquia departments, northwestern Colombia, where the full extent of its range is somewhat unclear. Type locality is 'Río Truandó, a tributary of Lower Río Atrato, Colombia', and it may be restricted to that system.

This species has something of a confused history having been previously been considered synonymous with both A. sophiae (a separate species native to Iraq and Iran) and A. cypris (currently considered a junior synonym of A. mento). Although some populations occur close to and even sympatric with other members of the genus in Turkey phylogenetic studies have shown it to be more closely-related to the Middle Eastern species A. dispar dispar, A. d. richardsoni, A. ginaonis and A. sirhani. It's...

The genus Aphanius currently contains 22 species and subspecies which are thought to have derived from a common ancestor originally distributed around the periphery of the former Tethys Sea. These can be separated into two main phylogenetic groups usually referred to as the 'eastern' and 'western' clades by scientists and aquarists because they broadly correspond to those coastlines of the Tethys. The eastern clade comprises the species now found in the Arabian Peninsula and ...

Wild swordtails are a fairly basic green colur. However the vast majority of swordtails available in the hobby today are hybrids of X.helleri with X.maculatus or X.variatus. There are a huge number of selectively-bred varieties available, including wagtail, lyretail, tuxedo, albino, neon, red, green and hi-fin. Swordtails may undergo what appears to be a change in sex. In young fish this may simply be late development. However some adult females develop male characteristics which is thought ...

This little-known, relict species possesses some unique morphological and behavioural traits when compared with its congeners and the genus Kosswigichthys was erected for it in the original description. It has a much more elongate body profile than other Aphanius spp., almost total absence of scalation on the body and three rows of conical (as opposed to tricuspid in all other species) teeth which set it apart. Work by Franz and Villwock in the 1970s revealed it to be a member of Aphanius and showed ...

Occurs naturally in Brazil, Paraguay, Uruguay and Argentina with feral populations in Australia, New Zealand, Ethiopia and Malawi which were purportedly introduced for purposes of mosquito control but are now considered invasive. Following Lucinda (2008) its natural range comprises the Lagoa dos Patos system, lower rio Uruguai, rio Tramandaí, and rio Mampituba in Rio Grande do Sul st...

The modified lower jaw and reduced scalation exhibited by this little-known species have seen it placed in the disused genera Anatolichthys and Turkichthys in the past and it is still sometimes listed as a species of Lebias although that generic name has long been considered a synonym of Cyprinodon by most authorities and an ICZN committee voted to suppress the name in favour of Aphanius as recently as 2003. You're unlikely to find it on sale in aquatic stores although it ma...

Need not be too complicated so long as there are plenty of broken lines-of-sight. Provide plenty of cover in the form of aquatic plants, wool mops, etc., and if using filtration air-powered, sponge-type units are best as these will not harm eggs or fry. Lighting is unimportant but can be use...

Tends to be most common in brackish to hypersaline environments such as coastal salt marshes, lagoons and estuaries. On San Salvador Island, Bahamas, it appears to be the parent of a species group occurring in sympatry and exploiting diverse but specific resources with some spectacular morphological adaptations.

The surrounding area is semi-arid and the Bolsón de Sandia was once a beautiful oasis with a number of springs, abundant vegetation and diverse wildlife but has dried up over the last twenty to thirty years due to indiscriminate water extraction for agriculture and other human uses. Three endemic species of Cyprinodon, namely C. veronicae, C. longidorsalis and C. ceciliae, have been described from separate springs within the system...

Endemic to San Salvador Island in the Bahamas where it's known from six hypersaline lakes; Crescent Pond, Osprey Lake, Oyster Lake, Little Lake, Wild Dilly Pond and Moon Rock Pond. Type locality is 'San Salvador Island, Bahamas: Crescent Pond, 1 km SE of the Gerace Research Centre, lat 24°06'45"N, long 74°27'28"W'.

This species is a specialised lepidophage with approximately 50 % of the diet comprising the scales of other fishes. Physical adaptations to this behaviour include its elongate body and jaw mechanism permitting a fast biting action.

El Pandeño de los Pando has a surface area of around 287 m² with depth ranging from 40-80 cm but there is an abandoned artificial channel which has an area of approximately 437 m². Water temperature fluctuates between 38-48°C/100.4-118.4°F and the spring is considered one of the hottest environments inhabited by fish in the world.

Despite often being referred to as extinct in the wild this monotypic species is still surviving at a few localities. It's not particularly scarce in the hobby with strong captive populations existing, some of which have been selectively bred to produce variations in colour and patterning. As with other goodeids, there is less of a size difference between the sexes than in many other livebearers. This is thought to be related to the relatively primitive...