Aquatic frogs are, to most hobbyists, very cute and appealing. On more than one occasion when I’ve had friends and their kids down to my fish room to pick out something for their tanks, the kids ended up in front of the dwarf frog tank. Keeping and selling frogs in your store is very easy, and they often will be chosen for a nano tank.
African clawed frog
To start with, it is very important to make sure of the species of frog you buy from your wholesaler. The two most common frogs offered for sale in the hobby are the African clawed frog (species of the genus Xenopus) and the true dwarf African frog (species of the genus Hymenochirus). The reason is what their eventual size will be when they are adults. True dwarf frogs only get to be 1 to 1 ½ inch in body size, and they are limited by the size of their mouth to eating only very small fish. Xenopus frogs get to a very robust 4 to 5 inches in body size ,and with a very large mouth. There have been many tales of woe from unsuspecting hobbyists who bought what they thought (were told) was a true dwarf frog, only to have it grow into a monster much larger than they expected—and it got to that size by devouring all of the small fish in the tank.
The surest way to differentiate between the two frogs is to carefully inspect their front legs and fingers. The true dwarf African frog has webbed front feet, with no claws at the end of the finger. The Xenopus frog has black claws on the end of each finger of both front and back legs; it is also a generally more rounded frog than the true dwarf, which tends to be thinner and flatter. There is also an albino/xanthic form of the Xenopus frog, while no albino for of the true dwarf frog is, to my knowledge, available in the hobby.
Taking care of both the true African dwarf frog and the African clawed frog is pretty much the same. If you get very small clawed frogs, keeping them together for a long period of time can be problematic, as it is possible for the larger ones to make a meal of the smallest ones. They require clean, filtered aquarium water, and prefer temperatures in the mid-70s. While they prefer small meaty things like brine shrimp, bloodworm or mysis shrimp, both of these frogs will eat absolutely anything.
One final thing needs to be mentioned. In many states, the Xenopus frog has become established in the local waterways, and they can be a real problem. Some states have outlawed the selling or keeping of them.