 The eel-like catfish of this region were long assumed to belong to the widespread species "Clarias nieuhofii" but examination of 6 specimens purchased from a fish market in Samarinda in 1999 and preserved specimens from the same location revealed consistent and distinctive differences indicating a separate species.This is an elongated catfish up to 30.8 cm (12.1 inches) standard length.Compared to "C. nieuhofii" it has a "neck" distinctly narrower than the head, giving the head an egg-shaped appearance when viewed from above or below and the overall colour is much darker