Can fish really drink water?

Surprisingly, the question is asked quite frequently. As simple as it seems, the concept is more difficult and interesting than one would think.

One hundred students from Antioch Community High School took a survey on whether they believe fish are able to drink water or not. 67 respondents answered yes and 33 answered no.

How do you define the word drink? This is kind of a trick question with a tricky answer. Although, every living creature must have water to live, fish do not actually drink water, instead, they absorb it through their skin. However, not all fish need to “drink.” Only salt water fish need to “drink” water. In freshwater, the fish is saltier than the water and does not need to use osmosis. Osmosis is when fish pass water through their skin and gills. Salt water fish use osmosis more often because the water contains more salt than they do.

Ultimately, the answer to the question is no. However, it does matters on how we define the word drink. Fish cannot drink water, they can only absorb it.