Went to get a betta today for my 10 gallon tank. I also got 3 tetra Glowfish. The lady at the LFS said it should be fine. I put them all together now and I don't think the tetras look very happy. I've been doing some reading and everything I've read said the tetras should be in schools of 6 or more and I would need a bigger tank. Should I take the tetras back?