Why do animals live in salt water?

Answer 1

Because god in His multi diverse abilities made them that way. That's the bottom line

It is believed that the first creatures on the Earth lived in the sea. Millions of years later some got the idea of living on dry land. So creatures that live in the salt water seas are just as naturally suited to their environment as those that live on land or fly in the air - evolution developed creatures in different ways.

Answer 2

Because they are Saltwater Fish and not Freshwater Fish. Like humans drink freshwater and not saltwater, because our bodies can't tolerate an intake of saltwater.

Answer 3

Yes. Salt water fish die when placed in fresh water due to the process called osmosis.