Biologic evolution

Does sea fish's urine consist of what?
Does the sea fish drink water?
I think that the sea fish drinks water.
Rain
Drain
Underground water
Meltwater

I think that the amount of necessary water is different depending on the size of the fish.
It is thought that it is a reasonable amount only because of one of rain in case of the fish of a small individual.
Water is a drunk thing, and no place where it lives.
The moisture how many days on earth has not water been drunk?
It is a problem.