Hypostomus plecostomus, the Suckermouth catfish or common Pleco is a tropical fish belonging to the armored catfish family (Loricariidae), named for the armor-like longitudinal rows of scutes that cover the upper parts of the head and body (the lower surface of head and abdomen is naked). Although the name Hypostomus plecostomus is often used to refer to common plecostomus sold in aquarium shops, most are actually members of other genera.

Pleco are of little or no value as a food fish, although they are at least occasionally consumed over their native range.A demand exists for them, however, in the aquarium trade. Plecos are well-known algae eaters that originated in the rivers of the Amazon jungle in South America. Plecos attach themselves to hard surfaces with specially adapted mouth parts. They are scavengers and will eat almost anything. Recommended for beginner aquarists.