I have two bullfrog tadpoles, they have there back legs, but they're really tiny, and useless looking. They live in a 10 gallon tank, with water filtration, and aeration. They have a raised area where the water is very shallow, and fake aquatic plants to hide in. I bought tadpole food, but they wouldn't eat it, so now they are back on tropical fish food. They seem active and healthy, they eat very well, twice a day. My Brother found them in a pond and had them for some time, they haven't grown much since he found them. I have raised this kind of tadpoles before with no problems, but these guys look so sad. Any ideas on what could be wrong?