An inventory of fish species was conducted in the Bering Glacier Region, Alaska, in 2002–2006. Ten species were collected: surf smelt, coho salmon, sockeye salmon, rainbow trout, Dolly Varden, threespine stickleback, prickly sculpin, slimy sculpin, Pacific staghorn sculpin, and starry flounder. All are either marine in origin or tolerant of salt water; consistent with this, fishes in the watershed tolerate a wide range of water qualities in fresh water. Stickleback, prickly sculpin, slimy sculpin, coho salmon, and Dolly Varden are found most commonly either because they are early colonizing species or they are able to out-compete early colonizers. Species that readily assume residence in fresh water were found equally often in isolated and connected lakes and streams, whereas diadromous and marine species were found primarily in lakes and streams with outlets. Except for Dolly Varden, species were more likely to be found in nonglacial than in glacial lakes and streams. Greater species richness was associated with the presence of aquatic vegetation and algae, both of which provide structural complexity and indicate more abundant nutrient levels in otherwise oligotrophic waters. With the exception of Vitus Lake, which is tidally influenced, fish species richness was low. Older lakes and streams support more species than younger aquatic habitats, presumably owing to greater time for colonization and the formation of habitat complexity. This ever-changing aquatic landscape has been colonized by typical fish species in the region, but these colonists have evolved in atypical ways, including populations of dwarf Dolly Varden and stickleback species pairs.