You've probably noticed that living creatures like animals and plants all seem to need water. But what about fish? Fish are living creatures, but since they already live in the water, do they need to drink water, too?
The answer is both yes and no -- it depends on the type of fish! Have you ever noticed that some fish live in salty water (like the ocean) while others live in freshwater (like lakes)? When it comes to drinking, freshwater fish and saltwater fish have different needs because both types of fish have to strike a balance between the amount of salt in their bodies and the amount of salt (or the lack of salt!) in the water around them.
Fish that live in freshwater do not have to actively drink water. Instead, these fish absorb, or soak in, the water all around them that is already just like drinking water! The bodies of these fish work to make sure that absorbing so much salt-free water doesn't thin out the amount of salt in their bodies.
On the other hand, fish that live in seawater do have to actively drink water. But since the water that they live in is so salty, their bodies process it to take out the salt so that they aren't overloaded by too much salt!
Some fishy geography!
Have you ever thought about the difference (for a fish!) between living in freshwater and living in salt water? Do you know which kind of water certain fish live in?? Goldfish, angelfish, rainbowfish, and kois are all kind of fish you might be familiar with who live in fresh water! Clownfish, eels, grouper, and pufferfish are all kinds of fish you might know about who live in saltwater!
Can you think of any other examples that you've seen at an aquarium or in a friend's fish-tank? Why do you think some fish live in freshwater, while others live in saltwater??