Freshwater bony fishes are ammonotelic. Marine bony fishes release trimethylamine oxide as their chief excretory product. Terrestrial insects, such as cockroach, are uricotelic, while aquatic insects are ammonotelic. Tadpole of a frog is ammonotelic, while the adult frog is ureotelic. All mammals, terrestrial as well as aquatic, are ureotelic in nature.