Do fish pee?

Yes they do! According to Nanfa, fish have active osmoregulatory systems which mean that fish do need to form and excrete urine to keep their body fluid in equilibrium. The amount that they excrete though depends on the type of fish.

Freshwater fish excretes large volume of dilute urine as they are constantly taking in the freshwater around them. Saltwater fish in contrary excretes small volume of concentrated urine as they are losing water to the environment.

So the next time you take a dip in the sea with a bunch of fish, you are swimming in their pee. No wonder, the sea is always “fishy“.

Picture source: Newpetmall.com