I agree with leopardess, if you were looking fo a second opinion on that. You could try a mystery snail, but it isn't an active fish. A 10 gallon would open your fish options. Otherwise the adf.
at one point I recomended to get a loach (pencil? or something I think- it is a skinny stick, maybe it was a black loach...I am no help) for my 5g. I didn't think the fish was appropriate, but maybe some research would reveal differently.
You could divide the tank and put 2 bettas, but that isn't giving him company, just a flaring partner, and less room.
