Squid constitutes the main diet of black fish.
Blackfish is a term used to describe various types of fish and two types of cetaceans. Fish commonly referred to by the term include Alaskan blackfish, Sacramento blackfish, and river blackfish. The melon-headed whale and killer whale, also known as killer whale, are also called by this name.
The Alaskan blackfish, Dallia pectoralis, is an olive-brown, cylindrical fish. The fish has four to six dark spots running vertically down the sides and has a white belly. The fins have reddish-brown spots. Reaching lengths of 7 inches (17.7 cm), the fish are found in Alaska and the islands of the Bering Sea.
“Blackfish” may refer to Alaskan black fish.
The Sacramento blackfish, Orthodon microlepidotus, is found in central California. This fish is the only member of the genus Orthodon. Dark in color throughout the body, the fish is lighter when young and darkens as it matures. Measuring 21.5 inches (55 cm) in length, the fish is common in the Sacramento and San Joaquin rivers. They are also found in the waters that flow into the San Francisco Bay.
Orca can be called “black fish”.
The river blackfish, Gadopsis marmoratus, is found in the freshwater of Australia’s Murray-Darling river system, from Queensland to Victoria. A nocturnal carnivore, the fish’s diet consists of crayfish, shrimp, and other small fish. Reaching lengths of 11.8 inches (30 cm), the fish are in decline due to overfishing, competition from introduced species, and stream siltation.
The melon-headed whale, Peponocephala electra, is sometimes known as the many-toothed blackfish or the electra dolphin. This whale is part of the dolphin family, or Delphinidae. The entire family is often called by the common name of blackfish. The killer whale, Orcinus orca, is also part of this family.
The melon-headed whale is found in most of the world’s tropical waters. The whale’s body is light gray and the face, which is shaped like a rounded cone, is dark gray. Reaching lengths of 10 feet (3 m), the melon-headed whale’s main diet is squid.
The killer whale is the only species in the genus Orcinus. With a black back, white sides, and a white chest, the killer whale has a white patch above and behind the eye. The calves have a yellowish hue that changes to white. Male killer whales average 20 to 26 feet (6 to 8 m) in length, with females 16 to 23 feet (5 to 7 m).