Usually its the african you find over here, the pixie frogs. There are 2 species of africans i don't think you'd consider one as better than the other. Miguel how are your africans and tomato frogs doing?
I have the african pixie in a 60 cm long tank. I glued a peice of glass and made a pool out of one corner.... They are happilly engorging themselves.
Also have a baby Pacman ( beautifull frog ).. It is in a 10 gallon tank.. Hardly mooves. Only when crickets are in the tank, which she avidly stalks...