Erethistoides senkhiensis, new species, is described from Senkhi stream, Arunachal Pradesh, India. It differs from all congeners except E. infuscatus in having a less strongly produced snout. It differs from E. infuscatus in having the body with three black to light brown cross bars on a dark grey to light brown background, fewer vertebrae (29-30) and a concave caudal-fin, in having the serrae on the posterior edge of the pectoral spine short, more convex anteriorly and distantly placed.
Erethistidae is a family of catfishes that inhabits South and Southeast Asia. Members of this family are small, cryptically colored fishes with tuberculate skin and well developed coracoid process. Members of the genus Erethistoides are small and poorly known, originally diagnosed from other erethistid genera in having a tuberculate skin a greatly depressed head and body. As a result of the discovery of additional species in the recent years the genus was re-diagnosed by two unambiguous synapomorphies, i.e. the neural spines of the first eight post-weberian vertebrae strongly depressed, inflected posteriorly, and positioned in a groove formed by the base of the neural spines of the vertebrae immediately posterior; an enlarged maxilla that is almost as long as the palatine. The genus now includes six species: E. montana, E. pipri, E. sicula, E. cavatura, E. ascita and E. infuscatus. They are known from India, Nepal and Bangladesh.
The specimen of Erethistoides collected during ichthyological surveys in Arunachal Pradesh include an undescribed species, which is described here as E. senkhiensis.