The true rana frogs are bullfrogs, leopard frogs, green frogs and frogs like these pictured above. These frogs are fantastic swimmers. Not all frogs are. In fact, frogs can drown. Not the case with these frogs. They never venture far from water in nature and will submerge when they feel threatened. A frog may seem a bit clumsy out of water but when swimming they are truly graceful and a pleasure to watch. My leopard frogs and bull frog swam in the pool when the chlorine level was low. And they hung out in the bath tub while their tank was being cleaned. And swimming is great exercise for these frogs.
Housing them depends on their size. Both the leopard frog and the bull frog are experts at the high jump so a screen on their tank is an absolute necessity! The bull frog can grow to be quite large so they require a very large tank and a big bathing bowl. The bullfrog would probably be happier in a pond. This is the frog jumped at the Calaveras frog jump and featured in the book by Mark Twain about the Calaveras frog jump. More than one leopard frog and more than one bullfrog can be housed together but you have to be alert for bullying. (sorry, I couldn't resist) and subsequent injuries and resultant infections. With bull frogs, make sure they are the same size! Room mates are fair game when they're hungry, especially if their room mate is a lot smaller. This is true of most frogs.
These frogs like crickets dusted with vitamins and calcium with vitamin D3 as do all frogs. Being bigger, night crawlers will also be appreciated and good for them. Both of these frogs are shy but the males less so. It is easy to distinguish the males since their ears (round membrane behind eye) is the same size or larger than the eye. The females ear is smaller. They are especially not fond of handling and will do their best to discourage you by squirming, wetting on you and sometimes croaking indignantly. They will croak for no apparent reason on occasion and the bull frog croak is quite loud. Hopefully your neighbors won't mind.