Baryancistrus demantoides is a species of armored catfish endemic to Venezuela.

It lives around granite rocks in flowing water, in the upper parts of Orinoco River.

[2] The colour is green-brown with yellow spots on the head and parts of the body.

The dorsal fin is connected to the adipose fin, a feature that distinguishes this species from the rest of the Ancistrini, except Baryancistrus niveatus, Parancistrus and Spectracanthicus.

The other is Hemiancistrus subviridis, which resembles B. demantoides in appearance, and it is this visual similarity that likely historically caused the two to be thought of as the same species, or at least closely related ones, leading them to share an L-number.