What is "kryptopterus"

Kryptopterus is a genus of catfishes belonging to the family Siluridae. They are found in freshwater throughout Southeast Asia. The scientific name comes from Ancient Greek kryptós (κρυπτός, "hidden") + ptéryx (πτέρυξ, "fin"). It refers to the reduced or even entirely absent dorsal fin of these catfishes.

These small- to medium-sized catfishes have opaque, transparent or translucent bodies, hence their common name Asian glass catfishes. Despite this name, only three described species have clearly transparent bodies: K. minor, K. piperatus and K. vitreolus. Most significant among these is the ghost catfish (K. vitreolus), which is the "glass catfish" most often seen in the aquarium fish trade. This species was initially confused with the larger glass catfish (K. bicirrhis; infrequent in aquarium trade) and subsequently with K. minor (essentially absent from aquarium trade). This matter was only fully resolved in 2013.