The question of proper and sufficient food for the fish in Crater Lake's almost chemically pure waters is often discussed. Since the only drainage into the lake is the small precipitation which falls on the cliffs from the Rim to the shore, any food carried into the lake from that source would be negligible. That food in sufficient abundance does exist is evidenced by the fact that the fish caught are always in excellent condition.

In the few shallows along the base of the talus under Glacier Peak and The Watchman, thousands of tadpoles were recently again observed, and frogs of at least two species, and this is at least one source of abundant food supply.