Ptychochromis grandidieri is a species of fish

Fish

Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...

 in the Cichlidae family. It is endemic to river basins along a large part of the eastern coast of Madagascar

Madagascar

The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...

, although it has been recorded as far as 100 kilometres (62.1 mi) inland. Uniquely in the genus Ptychochromis

Ptychochromis

Ptychochromis is a genus of fishes from the cichlid family. They are found in rivers and lakes in Madagascar, and a single species can also be seen in brackish water. Most species in this genus are threatened, and P. onilahy is probably extinct. Most reach a length of , but P. grandidieri reaches...

, this species also occurs in brackish water. It reaches a length of about 21.5 centimetres (8.5 in). It shares a large part of its range with a cichlid from another genus, Paretroplus polyactis

Paretroplus polyactis

Paretroplus polyactis is a vulnerable species of cichlid fish found widely in fresh and brackish water in coastal regions and associated river basins in eastern Madagascar. It is the only Paretroplus found in the southern half of Madagascar, and one of only two found in eastern drainages . P...

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