Amakusaichthys is an extinct genus of ichthyodectiform ray-finned fish which lived during the Late Cretaceous, known from two species A. goshouraensis from Kumamoto Prefecture in Japan[1] and A. benammii from Chiapas in Mexico.

[3] This site is later considered to belong to Hinoshima Formation of the Himenoura Group.

[1][3] Second species, A. benammii is described from Angostura Formation in Tzimol Quarry, Chiapas, southeastern Mexico.

[1] Multiple specimens are found overlapped in one place, suggesting its schooling ecology.

[5] However, the describers of A. benammii later placed both Amakusaichthys and Heckelichthys (with Garganoichthys and Altamuraichthys as other probable members) into a separate family Heckelichthyidae, and questioned the inclusion of Bardackichthys and Chuhsiungichthyidae within Ichthyodectiformes.