Bullfrogs only lay their eggs in permanent bodies of water, like lakes or large ponds. You can find their tadpoles along the shore on warm days, and they will look like frogs, because they sun themselves near the surface and submerge when you walk by. They are much larger than other tadpoles, and can get 4-5 inches long. The one I have is about 4 inches long and has tiny back legs sprouting. I should warn you, bullfrogs can get huge, especially a female, and for that you could find yourself needing a 100+ gallon aquarium!