What happens to a saltwater fish when it's put in freshwater?

Most freshwater fish are not adapted to saltwater conditions and cannot effectively osmoregulate. In freshwater a fish is hypertonic to its environment, meaning the fish is"more salty" and water continually flows into the fishes body via osmosis. In saltwater a fish is hypotonic or"less salty" compared to its environment. read more

These fish include salmon, smelt, shad, striped bass, and sturgeon, according to the Alaska Department of Fish and Game. Catadromous fish, on the other hand, generally live in freshwater bodies of water and only enter saltwater to spawn. read more