Onilahy is a river in Toliara Province, southern Madagascar. It flows down from the hills near Betroka to the Mozambique Channel. It empties at St. Augustin, and into the Bay of Saint-Augustin.
Arius festinus is a species of fish in the family Ariidae. It is endemic to Madagascar. Its natural habitat is rivers. It is threatened by habitat loss.
Bedotia sp. nov. 'Bemarivo'is a species of fish in the Bedotiidae family. It is endemic to Madagascar. Its natural habitat is rivers. It is threatened by habitat loss.
Bedotia sp. nov. 'Manombo' is a species of fish in the Bedotiidae family. It is endemic to Madagascar. Its natural habitat is rivers. It is threatened by habitat loss.
Bedotia sp. nov. 'Nosivola' is a species of fish in the Bedotiidae family. It is endemic to Madagascar. Its natural habitat is intermittent rivers. It is threatened by habitat loss.
Bedotia albomarginata is a species of Madagascar rainbowfish from the Mananara and Reinana river basins in Madagascar. It is threatened by habitat loss. This species was described by John Sparks and Leila Rush in 2005 from types collected near the towns of Vondrozo and Vevembe from the Sahapindra River, which is a tributary of the Mananara River, in Fianarantsoa Province.
Oxylapia is a genus of freshwater fish in the family Cichlidae. It contains the single species Oxylapia polli, known locally as the songatana. It is an endangered species, endemic to the Marolambo Rapids in the Nosivolo River in east-central Madagascar. It is threatened by habitat loss and sedimentation caused by deforestation. The only other single-species cichlid genus in Madagascar is Katria, and it is restricted to the same region as Oxylapia. In 2010, the Nosivolo River was designated as a Ramsar Site. The Oxylapia is the conservation flagship species for the district capital Marolambo.
Pachypanchax omalonotus, the powder-blue panchax, is a species of Aplocheilid killifish endemic to Madagascar where it is found on the island of Nosy Be and in the Sambirano River basin and adjacent streams on the mainland. Its natural habitat is rivers.
Pachypanchax sakaramyi is a species of Aplocheilid killifish endemic to Madagascar where it is only known from Sakaramy and Antongombato Rivers with reports that it is found in several crater lakes. Its natural habitats are rivers and freshwater lakes. It is threatened by habitat loss and invasive species.
Pachypanchax sparksorum is a species of Aplocheilid killifish endemic to Madagascar where it is found in the Anjingo River and streams feeding into the Ankofia River. Its natural habitat is rivers. The specific name of this fish honours the ichthyologist John S. Sparks of the United States National Museum and his wife Karen Riseng Sparks, they collected many of the type series.
Pachypanchax varatraza is a species of Aplocheilid killifish endemic to Madagascar where it is found in the Menambery, Fanambana and Ampanobe rivers. Its natural habitat is streams and pools. It is threatened by invasive species.
Pantanodon sp. nov. 'Manombo' is a species of fish in the family Poeciliidae. It is endemic to Madagascar. Its natural habitats are rivers and swamps. It is threatened by habitat loss.
Paratilapia typus is a species of fish in the family Cichlidae. It is endemic to Madagascar. Its natural habitat is rivers. It is threatened by habitat loss.
Ptychochromis loisellei is a species of cichlid from the Mahanara River basin north of Sambava in northeastern Madagascar. It remains common within its small range, but it is threatened by habitat loss and introduced species. It reaches about 11.9 centimetres (4.7 in). The similar named Paretroplus loisellei is also restricted to the Mahanara River basin. The specific name honours Paul V. Loiselle, Emeritus Curator of Freshwater Fishes at the New York Aquarium and a researcher in, and campaigner for the conservation of, the freshwater fish of Madagascar.
Ptychochromis curvidens is an endangered species of fish in the cichlid family. It is endemic to a few rivers that flow west from Montagne d'Ambre in far northern Madagascar. It is threatened by habitat loss and introduced species. It reaches about 14.7 cm (5.8 in) in standard length.
The trondo mainty is a critically endangered species of cichlid endemic to the Onilahy River Basin in southwestern Madagascar. Its remaining range covers less than 10 km2 (3.9 sq mi) and it is highly threatened by habitat loss, fishing, and competition with/predation by introduced species. Another cichlid from the same basin, Ptychochromis onilahy, is probably already extinct. The trondo mainty reaches a standard length (SL) of 24 cm (9.4 in).
Ptychochromoides itasy is a species of cichlid fish from central Madagascar. Until rediscovered in a pond at a tributary of the Tsiribihina River in late 2010, it was only known from Lake Itasy where last seen in the 1970s. The reason for its extirpation from Lake Itasy was likely habitat degradation and competition/predation by introduced species.
Katria is a genus of freshwater fish in the cichlid family. It contains the single species Katria katria, a vulnerable species from the Mangoro and Nosivolo Rivers in east-central Madagascar, that was formerly included in the genus Ptychochromoides. The only other single-species cichlid genus in Madagascar is Oxylapia, and it is restricted to the same region as Katria. In 2010, the Nosivolo River was designated as a Ramsar Site. The Katria reaches about 13 centimetres (5.1 in) in length.
Sauvagella robusta is a small species of fish in the family Clupeidae. It is endemic to the Amboaboa and Mangarahara River Basins in northern Madagascar. This relatively slender fish reaches a length of 6.8 cm (2.7 in), and is overall pale yellowish with silvery on the lower parts. Its current conservation status is unclear, but the cichlid Ptychochromis insolitus, which is highly threatened from habitat loss, is native to the same region. Sauvagella robusta is known to survive at least in Lake Tseny.
The two-finned round herring is a species of fish in the family Clupeidae. It is endemic to Madagascar. Its natural habitat is rivers. It is the only species in its genus.
