T. H. Bean, 1880
|Range of Dallia pectoralis|
The Alaska blackfish, Dallia pectoralis, is a fish that grows to 14 in (360 mm) in length, the largest of all umbridae. It is elongated 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. Once thought to be an herbivore, its primary diet is midges and mosquito insect larvae. Alaska blackfish are found in swamps, ponds, lakes, and streams with vegetation for cover, in tundra and forested locations not far inland. Their range includes Alaska and the Bering Sea islands. 
The hardiness of the Alaska blackfish is of mythical proportions, including tales of reviving fish after they are frozen solid. The fish survive the cold winters by moving to a depth of 7–8 m (23–26 ft) when the surface becomes solid ice. Large gills help them to survive the winters where the water temperatures drop to 0°C (32°F). The Alaska blackfish can be supercooled for up to 40 minutes at temperatures as low as −20°C (−4°F) in controlled environments without contact with ice crystals and survive.
- Froese, Rainer and Pauly, Daniel, eds. (2006). "Dallia pectoralis" in FishBase. January 2006 version.
- Mecklenburg, Catherine (2002). Fishes of Alaska. Bethesda, MD: American Fisheries Society. pp. 145–6. ISBN 1-888569-07-7.
- "Dallia pectoralis". Integrated Taxonomic Information System. Retrieved 30 January 2006.