Question

Why can’t salt water fish live in fresh water?

Answer 1

Saltwater fish have a different body chemistry than their freshwater counterparts. Their bodies have hypertonic cells, which keep more salt inside the cells (than outside of them). Therefore, putting them in freshwater will make the water rush into their cells and and eventually kill them.Before we delve further into this, it would be very helpful if we first understood the biological process of osmoregulation.

Answer 2

The osmolarity of salt water fishes is more than that of fresh water fishes and if they will go into fresh water then excess of water will enter in them hence they will eventually die of that. That is why they cannot live in fresh water.