Trachelyichthys is a genus of small driftwood (wood) catfishes in family Auchenipteridae, native to the Amazon basin in Brazil and Peru. Like other auchenipterids, they are soft-bodied, largely nocturnal catfish typically found sheltering among submerged wood and leaf litter in slow to moderate current, emerging to forage after dark.
These are diminutive fish, with atlas species reaching only about 1.5–3 in, and the pygmy driftwood catfish (Trachelyichthys exilis) is the species most likely to turn up in specialist catfish keeping, valued for its small size and secretive habits. The rest of the genus - T. displicatus, T. epachrus, T. gaiophanes, and T. varii - is little known outside ichthyological literature, and four of the five atlas species are Not Evaluated by the IUCN, reflecting how sparsely this group of small Amazonian catfishes has been surveyed.