Fish pass stool in a slightly different way than other animals. Instead of having an anus to expel waste, fish absorb nutrients from their food through the walls of their intestines and excrete the excess material through their gills. The process is known as urea cycle; it involves releasing ammonia into water, where it dissipates harmlessly into the environment. Fish also have kidneys that help filter out toxins, and they can use special muscles near their cloaca (the opening at the end of the intestine) to push out any remaining solids. To ensure healthy digestion in fish, owners should provide them with a balanced diet made up fresh fruits and vegetables as well as high-quality protein sources such as shrimp or worms.