I just wanted to tell you all that wonder about bettas sharing tanks with tetras that not much preparation is required to add tetras to a betta tank. Note: I am assuming that what I did will only work in large tanks(for a betta)like my 10 gal. tank. I bought 2 Phantom Tetras and a breeding container from PetCo. My original plan was to put the tetras in the breeding container to let them adjust. You should do this as well. As soon as Poseidon the betta lost interest in the fish and container(like 5 minutes), I rearranged my tank a little, to break up Poseidon's territory so he didn't think the Tetras were intruders on his land. After a while, I released the Tetras. The Tetras quickly found out not to come too close to Poseidon. They didn't go after each other at all. Naturally Poseidon was suspicious because this had been his turf for a week. If one came too close he would flare at them and come up to them. The tetras would always back off and there was no fighting. This does not mean my plan failed, as bettas do enjoy personal space. after a while, they settled things and Poseidon was mostly calm towards them. A pic of them with rearranged decor can be found under my aquarium tab. It's my only aquarium.