The removal of metabolic waste from the body to maintain the solute balance is called the excretion. Aquatic animals like Amoeba, Sponges, Hydra, earthworm, and fishes etc. excrete out the ammonia and ammonium ions. The excretion of ammonia is called ammonotelism and the organisms showing ammonotelism are called ammonotelic. Since ammonia is highly toxic and needs a high quantity of water to get dissolved, its excretion mainly occurs in aquatic animals.