In late Classical Greek art, an ichthyocentaur (Ancient Greek: ἰχθῠοκένταυρος, plural: ἰχθῠοκένταυροι, romanized: ikhthúokéntauros, ikhthúokéntauroi) was a centaurine sea being with the upper body of a human, the lower anterior half and forelegs of a horse, and the tailed posterior half of a fish.
The earliest example dates to the 2nd century BC, among the friezes in the Pergamon Altar. There are further examples of Aphros (Ancient Greek: Ἀφρός, romanized: Aphrós, lit. 'Sea Foam') and/or Bythos (Ancient Greek: Βυθος, romanized: Bythós, lit. 'Sea Depth/Abyss'), the personifications of the sea's foam and abyss respectively, depicted as ichthyocentaurs in mosaics and sculptures.
The term ichthyocentaur is of late coinage, attributable to the Byzantine writer John Tzetzes in the 12th century, and thus they are also referred as sea-centaur.