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 found beneath the head, surrounded by thick lips that have several soft lumps (papillae). These lips, coupled with tentacles and minute spines on the fin rays, enable the fish to adhere to solid surfaces in swift currents.