The Alaska blackfish (Dallia pectoralis) is a species of freshwater fish in the esocid family (Esocidae) of order Esociformes.

The color is dark green to brown on the dorsal side, pale below, with light-colored blotches appearing laterally.

[5] Another factor is the retention of the hydrostatic swim bladder, which seems unnecessary unless it is important in maintaining neutral buoyancy in the cold winter months under ice cover.

[3] Blackfish are found in highly vegetated swamps and ponds, occasionally residing in rivers and densely-vegetated lakes, where in summer, water is frequently stagnant.

[6] These breathing areas can be preexisting holes, such as those created by muskrats, beavers, and fishers, or simply thin layers of ice.

[6] In 1886, Lucien Turner reported an account of a frozen blackfish reviving after being thawed in a dog's stomach causing it to be regurgitated.

Metabolic and survival studies have been conducted have repeatedly failed to replicate this observation, finding that blackfish have no ability to revive any part of their body that had been frozen.

Further studies are warranted that estimate the abundance of introduced blackfish in lakes and streams in the Cook Inlet Basin, as well as investigate potential dietary overlap with other fish.