Low oxygen levels are pushing fish into shallower waters, with potentially devastating impacts for fisheries and ecosystems

Source: Science Daily

Fish can drown. While it may not seem like it, fish do require oxygen to breathe; it’s just that they get what they need from the oxygen dissolved in water rather than in the air. Too little oxygen spells trouble for our finned friends, which have to move or else suffer ill effects.

https://www.sciencedaily.com/releases/2021/09/210916142921.htm