Blackfish is a common name for various species of fishes and cetaceans, including:

• Alaska blackfish (Dallia pectoralis), an esocid from Alaska, Siberia, and the Bering Sea islands
• Black fish (Carassioides acuminatus), a cyprinid from China and Vietnam
• Black ruff (Centrolophus niger)
• Black sea bass (Centropristis striata)
• Black triggerfish
• Cornish blackfish (Schedophilus medusophagus)
• Gadopsis, two Australian freshwater fish:
  • River blackfish (G. marmoratus)
  • Two-spined blackfish (G. bispinosus)
• Galjoen (Dichistius capensis)
• Imperial blackfish (Schedophilus ovalis)
• Japanese black porgy (Acanthopagrus schlegelii), a large sea bream often cultivated in aquaculture
• Parore (Girella tricuspidata)
• Sacramento blackfish (Orthodon microlepidotus)
• Tautog (Tautoga onitis)

• Pilot whales (Globicephala)
• Melon-headed whale (Peponocephala electra)
• False killer whale (Pseudorca crassidens)
• Pygmy killer whale (Feresa attenuata)