Orinoco Sailfin Catfish

Pterygoplichthys multiradiatus is one of several tropical fish commonly known as Orinoco sailfin catfish, plecostomus (or plecos). It belongs to the armored catfish family (Loricariidae). Named for its sail-like dorsal fin, the part of its scientific name multiradiatus means "many-rayed" and refers to the rays of the dorsal fin. P. multiradiatus is one of a number of species commonly referred to as the common pleco by aquarists.

Other scientific names that were used (as synonyms) for P. multiradiatus include Hypostomus multiradiatus, Ancistrus multiradiatus, and Liposarcus multiradiatus. P. multiradiatus is sometimes confused with Pterygoplichthys pardalis, which is a different species of pleco. P. multiradiatus goes by a number of common names. It can be called the "long-fin armored catfish" in Hawaii, "sailfin catfish", "sailfish catfish", "many-rayed (multiradiatus) pleco" or "radiated ptero" in the United States, 多輻翼甲鯰 in Mandarin Chinese.