if a freshwater fish extracellular fluid has an osmolarity o

if a freshwater fish extracellular fluid has an osmolarity of 300 mOsm and freshwater has an osmolarity of 30 mOsm, would a freshwater fish take up or lose water by osmosis?

Solution

The fish is hyperosmotic compared to the fresh water surrounding it, because of which there is always a large amount of water entering the fish. To combat this, the fish produces large amounts of dilute urine and has specialized sensory organs to actively replace lost salts due to large amount of urine produced.