Marcusenius thomasi is a species of ray-finned fish in the family Mormyridae.

It is found in Guinea, Guinea-Bassau, Liberia, and Sierre Leone.

It is threatened by Mining and deforestation.

[1] The fish is named in honor of anthropologist Northcote W. Thomas (1868-1936), who collected the type specimen.

This Osteoglossiformes-related article is a stub.