Paretroplus loisellei is a vulnerable species of cichlid fish from the Mahanara River basin north of Sambava in northeastern Madagascar.

[2] Until its scientific description in 2011, this population was usually referred to as Paretroplus sp.

[2] It reaches about 15 centimetres (5.9 in) in length,[3] and is threatened by habitat loss and introduced species.

[1] The similar named Ptychochromis loisellei is also restricted to the Mahanara River basin.

[4] 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.