Pachypanchax (Killifishes)

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General Information for Aplocheilidae

The family Aplocheilidae currently holds 310 species within 15 genera and can be found in Africa, Madagascar, southern Asia, and southern North America to South America (Fishbase, 2007).

Only the genera Pachypanchax is found on Madagascar, with Pachypanchax playfairii the type species, being found on the granitic Seychelles islands, 650 miles (1050km) northeast of the northern tip of Madagascar. There are currently six described species, with the possibility of perhaps three more species being descibed after examination of museum specimens and further collection efforts.

The genus Pachypanchax was established in 1993 by Myers for Haplochilus playfairii and the then known two killifish species from Madagascar Poecilia omalonota and Panchax sakaramyi. A recent revision by Loiselle (2006) reexamined the definition of the genus Pachypanchax and, along with describing four new species, redescibed both P. omalonotus and P. sakaramyi.

Pachypanchax species are small, 3.0 inches (7.62cm) S.L., surface oriented fish with a flattened dorsal profile and superior oriented mouth. A single dorsal fin is placed far to the posterior of the body, well past the anal fin insertion. Caudal fins are rounded truncate, with heavy scalation to the basal half or more. Paired fins are hyaline, with the unpaired fins of males typically showing some colouration. Unlike Pachypanchax playfairii, the Pachypanchax species from Madagascar are not found in brackish water.

Although Pachypanchax species can be found in lacustrine environments and riverine areas of strong current, they are more often associated with tranquil pools in small streams or creeks. Apart from two species which are native to the eastward- and northward flowing drainages in the extreme north, Malagasy Pachypanchax are restricted to the island's western versant (Loiselle, 2006).

It should also be noted here that most literature published since 1950 purporting to deal with Pachypanchax omalonotus actually refers to the newly descibed species P. arnoulti, (Loiselle, 2006). This is because, contrary to popular belief, P. omalonotus has a fairly restricted range, being found only on Nosy Be, the Sambirano river basin, and in several small coastal streams on the Ankify peninsula.

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Husbandry Information for Aplocheilidae

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