Question

Why are freshwater fishes ammonotelic

Answer 1

ammonia is toxic in nature and requires alot of water so that it can be excreted ... since freshwater fish can compensate the water loss hence they are ammonotelic...
hope it helps!! :))

Answer 2

Fresh water fishes are ammonotelic organisms because ${NH}_{3}$ is highly toxic which cannot be stored in body so ${NH}_{3}$ requires very little energy formation.