So I have a 10 gallon tank, and I was wanting to house another betta in it. Would a divider be ok, or would it stress the betta's out because they can still see each other? I feel like 10 gallons is a little to big for my old betta (3 years old) but the only tank I have is a 13" x 7.5" x 8.5" Critter Keeper (it's plastic with no heater). What do you all think about dividers? Or should I just house my betta in the Critter Keeper? Thanks!