I have 2 bullfrogs (male and female) in a 55 gallon tank. Both are adult with the male being a little larger than the female. Both were captive raised from tadpoles. Neither jumps into the glass or up against the top cover when startled. I've provided lots of cover, strongly filtered water at swimming depth, and offer a variety of live foods. Bigger enclosures are ideal but so far my experience has been a successful one. This isn't an endorsement for the cage requirments of bullfrogs as the other opinions expressed here are valid. This is only my own experience.