do fishes....

Fishes do not pee exactly. Their soluble wastes such as urea are removed through their skin. Fishes live in water so they do not need kidneys to remove their soluble waste. It will diffuse through through their skin to the water surrounding them just like peeing, except you don't see them and it comes out little by little. Of course fishes cannot survive in their pee but the pee the secrete are being diluted by the water they live in. The fish will stay fairly healthy unless the concentration of their waste products rise to lethal concentrations. In an aquarium, you would clean and change the water regularly either with filters or anti ammonia chemicals (urea makes up most of the waste and they are ammonium compounds). In natural lakes, ponds, rivers and seas, there are living things that convert those wastes to less harmful substances. Certain microorganisms such as denitrifying bacterias convert ammonium to ammonia and they are present in water bodies such as ponds and puddles.

rotflmao Raclie, too funny. I know that fish do pee, but I had to go in search of a proper answer for you so here it is.... Fish do actually pee. Marine fish excrete very low volume of concentrated urine that is formed in the kidneys, as in other vertebrates. For the most part though, their nitrogenous wastes are excreted through their gills during respiration. http://zenandjuice.com/word/2004/11/26/do-fish-pee/