The eeltail catfish are a family (Plotosidae) of catfish whose tails are elongated in an eel-like fashion. Native to the Indo-West Pacific area (Japan/Australia/Fiji), the family of about 36 species in 10 genera includes both freshwater and marine types.

Most species have four pairs of barbels. The tail fin extends well up the back, and around to the anal fin below. Most types are small, with lengths of around 20-30 cm, but the gray eel-catfish can reach 150 cm (over 5 ft) and is fished commercially.