Kryptopterus cryptopterus (blue sheatfish) is a species of catfish, the type species of the genus Kryptopterus. It can be distinguished from all its congeners, with the exception of the newly split Kryptopterus geminus, by the almost flat dorsal profile with no concavity behind the head. This species grows to a length of 14.6 centimetres (5.7 in) SL.This distinctively shaped, translucent fish is found in Peninsular Malaysia, Borneo and Sumatra.