That won't work. ADF's (african dwarf frogs) need at least 1 gallon for each one and you could only have 2 ADF's in the tank and thats it you couldn't have the bettas in it either. Also if the divider didn't complety spilt the tanks the bettas could go under it and fight. So what you can do is go and get a sheet of plastic canvas and put it right down the middle of it (this will only work if its a minibowl aquarium that has the grooves in it) and you can put 1 betta on each side or you can put just 2 ADF's in it.