Plecostomus, pleco, or plec refers to several species of freshwater loricariid catfish commonly sold as aquarium fish:
- Hypostomus plecostomus
- Hypostomus punctatus
- Pterygoplichthys multiradiatus
- Pterygoplichthys pardalis
- Ancistrus cirrhosus
Pleco may also refer to:
- Pleco Software, an English–Sinitic dictionary application for iOS and Android devices, which uses the traditional Chinese character for "fish" (魚 yú) in its icon.