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Do Fish Drink Water? Yes or No!

For the freshwater fish that live in a river or lake, water tends to flow into their body through osmosis via their gills and skin, so they do not require drinking water while the saltwater fish drink a lot of water to stay hydrated and maintain the H2O balance in their body.

Fish are born and brought up in the water and meant to be there till death. But do all fish drink water?

You must have noticed the gasping movement of fish’ mouths underwater, but they do so to breathe in oxygen and during eating.

It’s pretty tough to understand if they are drinking water or not.

In summary, the answer to the question is, most fish don’t feel the need to drink water. Both marine and freshwater fish survive with the osmosis process through their gills and skin. At times, few saltwater fish may drink water to stay hydrated.

Do Fish Drink Water? The Detailed Explanation!

This thought can often tickle our minds when we look at a fish doing its gulping mouth action. But whether they are drinking water in the process, is completely impossible to understand.

Though fish live underwater throughout their lifetime, they can absorb water through osmosis and their gills to satiate their water requirements. Saltwater fish drink water while freshwater fish pass the water through their gills making sure that it doesn’t enter into their pyloric caeca.

Some saltwater fish do drink water to maintain an optimum fluid balance in their body.

While the saltwater fish direct some of the water they drink to their digestive tract; freshwater fish limit the water flow only to their gills.

Freshwater Fish

Freshwater fish do not feel any need to drink water. Though most of our curious minds might think, yes, freshwater fish do drink water, what happens is just the opposite.

In the case of freshwater fish that lives in a river or lake, water tends to flow into their body through osmosis via their gills and skin, which is a necessary bodily function for their living. Thus, they do not require drinking water.

Saltwater Fish

Those fish that live in the sea might feel the need to drink seawater. Brackish water fish need to drink a lot of saltwater from the sea to keep themselves hydrated.

To partially compensate for their bodily water loss, ocean fish drink a lot of water through their mouth. It helps them to have a healthy balance of fluid in their body.

To get rid of the salt they consume along with water, their gills pump excess salt outside their body.

Sharks, bony fish, tuna fish, and other fish that live in the ocean or sea are observed to exhibit the behavior of drinking seawater.

Tropical Fish

Similar to any other fish species, tropical fish uses the same process of hydrating themselves. Tropical fish do not require water for drinking purposes. They tend to use the osmosis process, like any other fish, to fulfill the water requirements in their body.

Do Fish Get Thirsty?

The answer is no.

Thirst usually implies the desire to drink water when our body feels the need for it.

Fish actively stay underwater, there are no chances for them to get dried out or dehydrated.

Their anatomy is not created in a way, which would allow them to have a thirst for water like us.

Fish stay hydrated all the time so they do not feel thirsty.

It is more applicable for land mammals and other animals that are not in direct contact with water.

How Do Fish Drink Water?

Now, this is a real thing to think about. If they do not drink water like us, then how do fish drink water?

The truth is instead of drinking water, fish tend to absorb it through their body. Usually, fish species can absorb water through their skin and gills through the process of osmosis.

Osmosis marks the passage of water across membranes. The water flows through the areas of lower concentration of solutes towards the areas of higher concentration. It participates in equalizing the concentrations of either area.

When it comes to freshwater fish, their body fluids and blood are way saltier than the water they inhabit. In such cases, the water will flow through their gills into their body. But the exact opposite scenario happens to saltwater fish.

The body of fish requires a particular concentration of salt for better functioning. If fish allow the water to diffuse freely through their gills and skin, the saltwater species will get shriveled up while the freshwater fish will tend to explode.

So, to prevent this, fish possess specialized cells in their gills that help in selectively pumping salt inside or outside of their body.

In saltwater species, their gills, along with kidneys, consistently help filter out salt particles.

On the contrary, the cells present in the gills of freshwater fish continuously pump salt into their body.

Frequently Asked Questions

Do goldfish drink water?

Goldfish do not feel the urge to drink water. Being freshwater fish, the water keeps flowing into their body through osmosis.

Do betta fish drink water?

Yes. Betta fish come with unique characteristics. Such special features allow bettas to absorb water while they swim forward.

Unlike other fish in which only gills and skin absorbed water, in bettas, the water passes through their body, gills, and mouth to keep the fish hydrated.

These fish possess tiny pores on their skin, through which water enters their body to meet their bodily water requirements.

Do jellyfish drink water?

Jellyfish do not drink water directly.

Jellyfish can suck water and salt from the marine water through their skin using the osmosis process for maintaining their usual bodily functions.

Jellyfish are one of those invertebrates, which survive in the water through this process.


Do fish drink water? Or do fish ever get thirsty? These are the probable questions to come up in our minds.

By now, you must have realized the truth that fish do not feel the need to drink water. Instead, they are formed in a way that helps them to quickly absorb water through their body and gills and let them have a hydrated body throughout.

Exceptions always exist, and that’s why some saltwater fish tend to drink water to compensate for their water loss from the body due to osmosis. Otherwise, the maximum of fish does not require drinking water.