The small mouth is located on the underside of the head, and has thick lips bearing several soft lumps (papillae). The lips, together with tentacles, and with minute spines on the fin rays, enable the fish to grip solid surfaces, so they can hold on in fast-moving streams.
The small mouth is positioned under the head and has thick lips covered by soft lumps. The lips, along with tentacles and tiny spines on the fin rays, allow the fish to grip solid surfaces, facilitating their ability to hold onto fast-moving streams.