Hello and welcome to FF! Currently we don't have a care article for the American Bullfrog; but most the info on this one applies: Frog Forum - Leopard Frog Care - Rana pipiens (Schreber, 1782) and R. sphenocephala (1886). Also; if you use the forum's search function, can find some discussion about their care in forum threads like this one: http://www.frogforum.net/care-sheet-...caresheet.html.

Bullfrogs do well in a large tank divided around 25-33% dry and 66-75% wet areas. Adult males can be housed in a 55-75 gallon tank. Adult females are larger and will require 75-100 gallon tanks. You can cover tank with screen tops made for reptiles in all common tank sizes. Bullfrogs will be fine at normal human room temperatures. You have to make sure the pebbles are too large for frog to swallow accidentally, if they are small, please remove them to avoid frog from swallowing them and becoming impacted. Good luck !