What is fish osmoregulation?

Osmoregulation in Fish:

1. Osmoregulation is the process by which an organism regulates the water and electrolytic balance in its body to maintain homeostasis.
2. Fishes live in both freshwater and marine environment, both have different levels of salinity.
3. In order to maintain homeostasis, fishes osmoregulate.

1. Osmoregulation in Freshwater Fish:

1. In freshwater, the concentration of salt is higher, therefore fishes have a hypertonic environment.
2. They absorb a controlled amount of water through the mouth and the gill membranes.
3. Due to this intake of water, they produce large quantities of urine through which a lot of salt is lost.
4. The salt is replaced with the help of mitochondria-rich cells in the gills.
5. These cells absorb salt into the blood from the surrounding water.

2. Osmoregulation in Marine Fish:

1. In marine water, the level of water is higher than salt.
2. Consequently, it results in the tendency to lose water and absorb the salt.
3. To get around this problem, marine fish drink large quantities of water and restrict urination.
4. Another additional energy expenditure also arises as these organisms actively need to expel salt from the body (through the gills).