Once tadpoles completely metamorphosed into froglets, we counted them and then randomly selected 10 individuals without any malfor mation from each tank to determine SUL and body mass. Metamorphosis rate (indicative of survival rate in the larval period) in each tank was calculated by dividing the number of metamorphosed froglets by the number stocked, and metamorphosis time was defined as the time interval between GS 25 and GS 46.