How does a piranha excrete?

Piranhas excrete waste primarily through their kidneys, which filter out toxins and excess salts from their bloodstream. They expel nitrogenous waste products, such as ammonia, directly into the water through their gills and via urine. This process helps maintain their internal osmotic balance and removes harmful substances from their bodies. Additionally, piranhas excrete solid waste through their digestive system after processing their food.