Amphilius is a genus of small African catfish in the family Amphiliidae, sometimes called mountain or torrent catfish for their preferred habitat: fast, rocky, highland streams and rapids across sub-Saharan Africa. The atlas's 14 species, mostly under 7 in, are drawn from Tanzania, the Democratic Republic of the Congo, Kenya, Zambia, Burundi, Guinea, Côte d'Ivoire, and Gabon, a spread that tracks the broken, hilly drainages where the genus tends to turn up rather than the continent's big lowland rivers. Like other current-adapted stream catfish, Amphilius species typically have a flattened head and body and enlarged paired fins that help them hold position against strong flow, a body plan that converges, without being related, on the hillstream loaches of Asia.
The genus is of far more interest to ichthyologists and biogeographers than to the aquarium hobby, where it is essentially unknown; the marbled mountain catfish (Amphilius jacksonii) is one of the few species to carry an established common name. Many Amphilius species are narrowly distributed to a single river system or highland block, which shows up in the conservation numbers here, with three species listed as Vulnerable, one as Endangered, and several more still unassessed, a pattern typical of small-range stream fish that are easy for survey work to miss and vulnerable to any disruption of their particular stretch of fast water.