Do Fish Get Thirsty? Do They Drink Sea Water?

There are a lot of amazing facts about fish that’ll make our jaws drop. It is probably the only species on Earth with the most varieties. There are over 32,000 types of fish on the planet. 

Do Fish Get Thirsty?

No, they don’t have the sense to feel thirst but yes, they do drink water. But, before we get on to how they actually drink water, it is essential we classify them first based on the salinity of the water they live in. 

Freshwater Fish

Freshwater fish don’t drink water. This is because the salt concentration in their blood and body is higher than their surrounding water. Drinking water might dilute the salt concentration in the body leading to death. This is the reason freshwater fish hardly drink any water. However, very little is ingested through the skin and gills and are excreted through urine. This process through which fish absorb water through their skin is called osmosis. 

Saltwater Fish

On the other hand, the concentration of salt is very much less in a saltwater fish’s blood and body compared to the water surrounding it. Hence, osmosis takes place the other way around. The water from the fish’s body moves out through its skin and gills putting it at a risk of dehydration. In this case, saltwater fish drinks water profusely through their mouths to counter dehydration. This is the reason why several freshwater fish varieties die when left in seawater. The increased salinity of the saltwater and the inability to drink water dehydrates freshwater fish leading to death. 

However, certain fish varieties like Salmon, eels, and flounder are formed in such a way as to survive in both freshwater and saltwater environments. An interesting fact is that the amphibious fish called Wooly Sculpin are said to survive for the longest time outside water, which is 24 hours.