They look like African dwarf frogs to me. I have two in a 6 gallon tank.
They don't do much, they like to sit around mostly, but sometimes at
night you can here them make noises. I made the mistake of putting
them in a tall 30 gallon tank at first, and they had a hard time of getting
to the top for air, so I put them in a smaller tank with a few harlequins , 2 frogs and a couple of small shrimp. They are doing fine.