Blackfish is a common name of fish.
Species which are called blackfish include:
Alaska blackfish, Dallia pectoralisBlack sea bass, Centropristis striataSacramento blackfish, Orthodon microlepidotusTautog, Tautoga onitisParore, Girella tricuspidataRudderfish, Centrolophus nigerGadopsis, two Australian freshwater fishGaljoen, Dichistius capensisJapanese black porgy, Mylio macrocephalus, a large Japanese sea bream often cultivated in aquacultureTypes of cetaceans, commonly known as whales, dolphins, and porpoisesMelon-headed whale, Peponocephala electraKiller whale (Orca), Orcinus orcaPygmy killer whale, Feresa attenuataFalse killer whale, Pseudorca crassidensLong-finned pilot whale, Globicephala melasShort-finned pilot whale, Globicephala macrorhynchus