y do saltwater fish need saltwater?

[forsaken]

anyone wanna go into detail of a saltwater fishes body as of why salt makes a difference? Is there some kind of organ that needs salt? weird question ik but ive always been curious.

 

[knifegill]

Osmoregulation. Their entire body needs the salt around it and in it for chemical processes to work. If you put a saltwater fish into freshwater, it will swell up and die because the water outside will rush in to fix the osmotic imbalance.

 

[duster1971]

the above info seems corect but im no expert post this in general salt or have a mod move it for ya as im sure kevin888 or mr reef can answre this in full detail for you