An ADF is an African Dwarf Frog. They are totally aquatic frogs, and since they only grow to a few inches long, they are popular for people to keep with bettas (siamese fighting fish) as they need similar food and are about the only thing that can be kept successfully with bettas in a small space. Look on the amphibians forum, and if you get one, make sure its not an ACF (see amphibians board)