Does a fish drink? All living things must drink,and they require a fresh supply of water often. A person can go with out food for many days , but he or she cannot go for long with out water. fishes drink and fishes that live in salt water. however,when we watch them in an aquarium and see the opening and closing their mouths , we must not assume that they are drinking. fishes need on the other hand,when a fish drink, it swallows water , just as we do