Two Betta fish in the same tank
Ok, so I have two “Siamese Fighting Fish” (a.k.a. “Betta” fish) at the moment, and I had one in a community tank and the other in a large vase. The community tank is a bit aggressive, there is a Red-finned shark that harasses a lot of the other fish. He hasn’t injured any fish that I know of, but he chases them when they come near the bottom of the tank.
With a large Angelfish keeping the fish at the top of the tank in check I figured I may have the right kind of crowd to make for a tank that can house two Betas in one tank. See, everyone “knows” that you can’t do this. The conventional wisdom is that they will “fight to the death. But in the wild, that is just not true, the weaker fish will usually flee. However in a small tank there is no opportunity to flee so the Bettas can actually kill each other.
In any case, the experiment seems to be working. They have both been in the community tank for a week now and the larger one only chases the smaller one for a second or two and they’ve not even touched. It’s a tentative peace, based on the smaller one being afraid enough and the larger one being uncomfortable enough around the red-finned shark and the angelfish. I don’t recommend it for novice aquarium keepers but for those with experience with difficult fish pairings and with a large tank with the right crowding and enough places to hide this can be done. They will chase each other briefly at most and have not fought.