Atheriniformes

This species was first imported for the aquarium hobby during the 1950s and was for many years misidentified and traded as Bedotia geayi, a valid, but different-looking congener native to the Mananjary River system, south of the range of B. madagascarensis. In terms of external characters, the two are most easily told apart by differences in colour pattern, particularly that of the unpaired fins, and some morphometric counts.

There also exists a sister-group relationship between the Melanotaeniidae and Malagasy family Bedotiidae, which may seem surprising given their respective modern-day distributional patterns. The precise origin and subsequent dispersal of the two families has been the subject of debate, with some palentologists suggesting that Madagascar's freshwater fishes derived froma trans-oceanic dispersal during the Cenozoic Era, but the most compelling arguments currently indicate a freshwater radiation which occurred during the Mezozoic break-up of Gondwana.

For many years, this species was included in the genus Telmatherina, and is still listed as such in much of the avilable literature. In fact it's now the only species in the recently erected genus Marosatherina. Unfortunately, it has been overfished for the aquarium trade in its native waters and is listed as 'vulnerable' on the IUCN red list of threatened species. Thankfully, it's now being mass-produced on fish farms in both the Far East and Eastern Europe, meaning that few...

M. affinis was one of the first rainbowfish species to be imported for the hobby in any numbers. There are several geographical variants, three of which can be found in the hobby. The "standard" form has a large natural range and is the most commonly encountered. The "Pagwi" form has a very limited distribution, being known only from a tributary of the Sepik River in New Guinea, while the "Bluewater Creek" form has only been collected from a single location close t...

This species was formerly classified as part of the Melanotaenia splendida complex, but more recent research into the genetics of the species has shown that not only is M. australis genetically dissimilar to the splendida group, but also that there are 2 clear lineages within australis This may yet result in another official member of the genus. M. australis exhibits a wide variation in colour and patterning depending on locality, and is probably the commonest rainbowfish species in Australi...

Also known as the Murray River or crimson-spotted rainbowfish, this species is not as common in the hobby as some of its relatives, but can still be found from time to time. It is easily confused with the very similar M. duboulayi, indeed these two were once grouped together as a single species. However, there are clear differences in patterning, fin ray counts and the way in which their eggs and fry develop. The range of M. fluviatilis extends further south than any other rainbowfish, and a...

Unfortunately the prisitine environment form where this fish comes is being threatened by overfishing (much of it for the aquarium trade) and industry, with an oil development being built at one end of the lake during the 1990s. M. lacustris has therefore been given "vulnerable" status on the IUCN red list. The lake was designated a Wetland of International Importance in 1998, as both it and the Kikori Basin where it lies contain some of the earth's greatest biodiversity in terms ...

There are a few geographical variants of this species available, which differ in colour, patterning and less commonly, size. These should not be mixed in aquaria, as they may hybridise. The differences are so apparent between some of these forms that they may well turn out to be different species in the future....

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There are currently 4 described subspecies of Melanotaenia splendida. The principle differences are generally in colour, pattern and fin counts, although even these vary depending on the locality of the fish. The different forms and subspecies should not be mixed in the aquarium, as they may hybridise. Adult specimens are rarely seen for sale, and it's the much drabber juvenile fish that are almost always offered in dealers tanks. However, exercise some patience (even on a good diet, full c...

There are currently 4 described subspecies of Melanotaenia splendida. The principle differences are generally in colour, pattern and fin counts, although even these vary depending on the locality of the fish. M s. splendida in particular also exhibits a wide variation in colour and patterning depending on locality within the subspecies, and the species name is often suffixed with a place name when the fish are seen for sale. The different forms and subspecies should not be mixed in the aquarium,...

M. trifasciata exhibits a wide variation in colour and patterning depending on locality, and it's very important that the different morphs are not mixed in the aquarium, as they will hybridise freely. These different forms are often distinguished by the addition of the name of collection locality being added to the scientific name of the fish. It's thought that several species may in fact be in evidence here, and a reclassification will probably occur at some point As with many othe...

Euryhaline and thus capable of withstanding significant fluctuations in salinity and other water conditions. It's been recorded in full marine conditions as well as pure freshwater environments, and commonly inhabits coastal mangrove creeks and swamps. Such changes may occur on a daily or seasonal basis depending on locality, with some habitats influenced by daily tides whereas others become hypersal...

This species is also traded as 'forktail rainbowfish' or 'yellow forktail', and it's also undergone several changes in scientific name since description. Pseudomugil furcatus is the original designation, but Allen (1980) created the genus Popondetta for it on the basis of morphological characters including number of anal-fin rays (16-20 in P. furcatus, 8-12 in other Pseudomugil spp.), absence of anterior...

Described from 'Rivulet in sago forest at Ngaiguli, Terangan, Aru Island, Aru Islands, Maluku, Indonesia', corresponding to the island now normally referred to as 'Trangan' in the Aru Islands group, eastern Indonesia. The islands are located in the Arafura Sea, with western New Guinea to the north and the Arnhem Land Region of Australia's Northern Territory to the south, and though they lie within Maluku province of eastern Indonesia, are part of the Australian continent in a geological sense.

Generally found within 15-20 km of the sea but habitat-type is extremely variable. It's been recorded in full marine conditions as well as pure freshwater environments, and commonly inhabits coastal mangrove creeks, swamps, and salt marshes. Freshwater habitats tend to comprise lowland swamps or forest streams with clear water but some populations inhabit acidic, tannin-stained, black waters. It's also abundant in the artificial canals typical of residential zones in the Gold Coast, southern Queensland.

This fish first appeared in the aquarium hobby in 2011 and has been traded under various names including P. sp. cf. paskai, P. sp. 'red orange neon', P. sp. 'neon orange', P. sp. 'Irian' and P. 'iriani'. The majority of fish available tend to be male, presumably due to their brighter colour pattern. It was initially suspected to be a hybrid or sele...

Euryhaline and mostly inhabits coastal floodplains where it's found in both fresh and brackish habitats, including tidal estuaries and salt marshes. It's particularly common in swamps, billabongs, and slow-moving streams where aquatic vegetation grows densely, but some populations have colonised upper sections of freshwater streams. Larger individuals may also move into main river channels. Tappin (2010) gives the following ranges of parameters based on those taken from various localities: temperature 27 - 38 °C, pH 5...

There are currently 4 described subspecies of Melanotaenia splendida, of which this species is one of the most colourful. The principle differences are generally in colour, pattern and fin counts, although even these vary depending on the locality of the fish. The different forms and subspecies should not be mixed in the aquarium, as they may hybridise. Adult specimens are rarely seen for sale, and it's the much drabber juvenile fish that are almost always offered in dealers tanks. However,...

A rarely seen species in the trade, although it's kept quite often by Australian hobbyists. Members of this genus are thought to have a more ancient association with Australian freshwaters than most others found in these habitats. Craterocephalus also contains the most species of any Australian freshwater fish genus. It has been shown that there are quite large genetic differences between groups of the species living in close proximity to each other, and even sharing the same waters. In ...

Also known as the salmon-red or New Guinea rainbowfish, this is one of the most popular rainbows in the hobby. Unfortunately, the colouration of today's mass-bred specimens is not even close to the spectacular wild fish. If you can find wild specimens they are well worth it.

Lake Wanam has been the subject of a management project co-ordinated by famous aquarist Heiko Bleher, who became concerned by an apparent drop in numbers of both this species and the barred rainbowfish (Chilatherina fasciata), which is also found in the lake. The drop in numbers is thought to be a result of the introduction of non-native Tilapia, Gambusia and carp species into the lake, along with a significant increase in the number of humans living in the area. G. wanamensis is now considered ...

This uniquely-patterned species is one of the most popular rainbowfish in the hobby and can be found swimming in most dealers' tanks. However, virtually all these fish are mass-produced on fish farms in the Far East and Eastern Europe. M. boesmani is actually quite rare in nature, and is on the IUCN red list of endangered species. Unfortunately this is one species on which the aquarium trade has had a massively detrimental effect, with an estimated one million fish a year being collected to...

This uniquely-shaped rainbow is an uncommonly seen species in the hobby, mainly because it hails from such a remote area in Australia. It is currently listed on the IUCN list of threatened species as being at risk, so all attempts at captive spawning are to be encouraged....

One of the more beautifull-coloured rainbowfish available when mature, M. herbertaxelrodi is probably at risk from overfishing, but not enough data is available to consider it an endangered species as yet....

This beautiful rainbow is not often seen in the hobby. It can be identified by the fact that the middle rays in the dorsal and anal fins are longer than the other fin rays. This feature is usually associated with the closely-realated Glossolepis genus of rainbowfish....