Akysis vespertinus

<em>Akysis vespertinus</em> is a freshwater catfish in the family Akysidae, a group of small benthic torrent catfishes native to stream and river systems of South and Southeast Asia. Adults typically reach a maximum recorded length of approximately 3.43 cm, consistent with the characteristically small size of most <em>Akysis</em> species. The specific epithet <em>vespertinus</em> — meaning of or belonging to the evening — may allude to the nocturnal or crepuscular activity pattern believed to characterise many catfishes in this genus, which tend to remain concealed under rocks and substrate during daylight and become active after dark to forage. Like other akysid catfishes, <em>Akysis vespertinus</em> is thought to inhabit well-oxygenated, fast-flowing hill streams and mountain tributaries, where strong currents, rocky substrates, and cool water temperatures define the environment. Its dorsoventrally flattened body, fin spines, and roughened skin texture enable effective substrate grip in rheophilic zones. The species is presumed to feed on small benthic invertebrates, periphyton, and detrital material. Details of habitat and range for this species remain limited in the ichthyological literature. Many species of <em>Akysis</em> are described from limited specimens collected during targeted surveys, and baseline data on abundance and distribution remain sparse. <em>Akysis vespertinus</em> has not been assessed for conservation status.