Ptychochromis grandidieri is a species of fish in the family Cichlidae endemic to river basins along a large part of the eastern coast of Madagascar, although it has been recorded as far as 100 km (62 mi) inland.

[2] Uniquely in the genus Ptychochromis, this species also occurs in brackish water.

[2] It reaches 35cm in standard length.

[3] It shares a large part of its range with a cichlid from another genus, Paretroplus polyactis.

[4] The specific name honours Alfred Grandidier (1836-1921), the French naturalist and explorer who, with Henri Joseph Léon Humblot (1852-1914), collected the type.