Blackfish is used in common names of several small freshwater fishes and some cetaceans of the oceanic dolphin family.

Fish

Family: Umbridae (mudminnows)
Species: Dallia pectoralis (Alaska Blackfish)

This fish grows to 7" in length. It is elongate and cylindrical, with a dark olive-brown coloration. Four to six dark blotches run vertically along the sides, and the belly is white. The fins have reddish-brown speckles. They are found in swamps, ponds, lakes and streams with vegetation for cover, in tundra and forested locations. Their range is Alaska and the Bering Sea Islands. Alaskan natives used to eat these fish a great deal, catching them in the fall and freezing them for use over winter.

Family: Cyprinidae (minnows)
Species: Orthodon microlepidotus (Sacramento Blackfish)

This fish grows to 18" in length and is elongate and cylindrical. The back is dark gray, shading to a lighter gray on the sides and below. They are found in the Sacramento-San Joaquin rivers, Clear Lake, a few rivers in California, and in the Truckee River in Nevada. Their habitat is primarily warm fresh waters with very little movement. It is a filter feeder of freshwater plankton. It has commercial value, being sold to oriental fish markets in San Francisco.

Black sea bass Centropristis striata is called blackfish in New England and the East Coast.

Family: Labridae (cunners/bergalls, tautog, wrasses)
Species: Tautoga onitis

In the saltwater areas around New York, tautog is also referred to as blackfish. This leads to confusion because different geographical areas refer to the same species of fish with a different name. Fortunately there is a scientific classification system to sort through this type of confusion.

Cetaceans

Blackfish is also a common name for six cetaceans commonly called whales but classified scientifically in the Delphinidae or oceanic dolphin family.

• Melon-headed Whale, Peponocephalia electra
• Orca (Killer Whale), Orcinus orca
• Pygmy Killer Whale, Feresa attenuata
• False Killer Whale, Pseudorca crassidens
• Long-finned Pilot Whale, Globicephala melas
• Short-finned Pilot Whale, Globicephala macrorhynchus