Do Fish Drink Water? Here's How They Survive In Saltwater

A fish as a pet is not a particularly fun thing, but a fish as a free animal in seawater is a very interesting organism to study.

Have you ever kept a fish as a pet? Have you ever wondered if it drinks water or not to dilute nutrients inside its body? If your answer is yes, then read on to find out more!

Fish breathe through their gills, unlike humans who breathe through their lungs. Fish are mostly carnivores and eat smaller fish, crustaceans, worms, and sometimes humans (in the case of sharks).

Whale sharks are the largest breed of fish. The most common pet fish is a goldfish. You must have seen a goldfish somewhere in the market or at your friend’s house or you might have a pet goldfish yourself.

You may also have seen some bubbles in the water tank of a fish and may have seen what you think is a fish drinking water. But do fish really drink water? Well, let’s find out if freshwater fish as well as saltwater fish drink water. Afterward, also read about do fish have eyelids and do fish have livers.

Do fish get thirsty?

This is a very interesting question. Fish are born in water and mostly die in water too. A fish dies out of the water usually when someone hunts for it and brings it out. The presence of water for a fish is as vital as the presence of air for us.

As we rarely realize that we gasp air with our mouths, a lot of times a day, a fish does not realize that it is drinking water through its mouth. Fish do drink water, but not to quench thirst, sometimes they drink it accidentally.

When taking it in for the proper functioning of their bodies, they do it mostly through their skin through osmosis instead of their mouths.

The answer to the question 'do fish get thirsty?' is not clear. But with given facts we can assume that fish do not get thirsty underwater. Like humans, fish need water to function their bodies, but they do not get thirsty.

Do fish drink water?

Like any other animal, a fish also drinks water for the effective functioning of its body organs. Almost all organisms need oxygen to survive. We take oxygen from the air we breathe and fish take oxygen from the water around them.

Water contains dissolved oxygen, so fish drink water and absorb that dissolved oxygen for their survival. This is the main reason behind the drinking of water by fish.

As per science, fish constantly drink water in their mouths, as all other organisms do. But fish also absorb water through their skin and gills through the process of osmosis.

The amount of water intake depends on the type of water. Fish in saltwater or seawater have to drink and absorb more water in order to stay hydrated while fish in freshwater have to urinate more in order to prevent hyperhydration and maintain a balance of water inside their bodies.

As a fish drinks water or takes it into its skin, what happens is, water flows through its gills, where the exchange of gases takes place. In the gills, the water gives oxygen to the fish and takes the carbon dioxide released by its body. This is how a fish breathes through gills underwater.

Do saltwater fish drink water?

Yes, all fish constantly drink water through their gills; this includes saltwater fish too. In fact, saltwater fish need to drink a lot more water than freshwater ones. This is because of the process of osmosis. Osmosis is a process by which a solvent moves from lower concentration to higher concentration through a selectively permeable membrane.

The water inside the body of a saltwater fish in the ocean has a low concentration of excess salt as compared to the water around their bodies (seawater or saltwater). Water flows from a less salty area to a saltier area.

So the water flows from inside of the fish’s body to outside of it, that is, the sea, ocean or other saltier water bodies, through the membrane. This makes the ocean fish dehydrated, and to hydrate itself, the fish drinks more water.

The opposite case is with freshwater fish. Freshwater fish have a higher concentration of salt inside of their bodies and the river or the freshwater body has a lower concentration of salt.

So the water flows inside the fish’s body through the permeable membrane and the fish gets swollen. To maintain the concentration of excess salt inside its body, a freshwater fish has to urinate more to get rid of excess water.

As per science, the main reason behind saltwater fish drinking water constantly is to maintain a balance in the process of osmosis and to breathe. It may sound weird, but all fish drink water underwater and also pass urine underwater. This is why they instantly die when brought outside the water. They can’t breathe from the air.

Do all sea fish drink water?

The main reasons behind Earth being a habitable planet is that it has a definite type of atmospheric environment and that it has water. All organisms in this world need water to live. No water means no life.

According to science, every organism needs water to survive, even if it lives underwater, especially so, actually. All fish drink water, no matter in which type of water they live.

The type of water may affect the amount of water intake. A seawater fish needs to drink water more frequently than a fresh water one, and the reason behind this has already been explained.

There is an exception to this: sharks. Sharks are the opposite as they have very salty blood which makes the salt level of their body almost the same as the salt level of the water body (sea or ocean).

So, sharks do not have a need to drink water to balance the process of osmosis. They do not have to get rid of excess salt or excess water from their bodies, because this is the natural state for them. They drink water only to breathe oxygen.

Here at Kidadl, we have carefully created lots of interesting family-friendly facts for everyone to enjoy! If you liked our suggestions for do fish drink water then why not take a look at do fish have tongues or do fish need oxygen.