Most definitely! You could divide it into 2 and still there would be adequate space... and you could have 2 bettas! I wouldn't do the shrimp though - tried that with my bettas and they bit them in half! argh. I would say, get some african dwarf frogs and 1 betta, see how they do together... if they are OK, then get a divider and get another betta! You can always send the frogs over the divider to the new betta to see how they get on too.... not all bettas will tolerate tankmates! Be warned though, you have to hand feed frogs... I use a turkey baster with bloodworms to make sure they get fed.