Ammoglanis obliquus is a species of pencil catfish endemic to the Rio Preto da Eva drainage in the central Brazilian Amazon.

[1] Ammoglanis obliquus, a minute catfish species reaching a maximum adult size of 15.5 mm, is described from the Rio Preto da Eva drainage in the central Brazilian Amazon.

Ammoglanis obliquus is regarded as more closely related to A. pulex than to any other congener, as both species exhibit a similar colour pattern, an absence of the metapterygoid, and the presence of two finger-like projections on the chin region.

Known only from its type locality in Rio Preto da Eva drainage, Amazonas river basin, northern Brazil.

[1][3] From the Latin obliquus, meaning oblique, referring to the conspicuous diagonal banded coloration pattern of living specimens.