I have a 45 gallon tank. In it is 6 male guppies, 2 painted tetras, 1 guamy (sp?), 4 cardinal tetras, 2 swordtails (1 male & 1 female), 1 hi fin neon serpae tetra and 2 other fish given to us so I'm not sure what they are lol. Anyways my question is that the serpae seems to chase all the other fish around and tries to nip at them. If he can't catch one he turns and goes after the next closest fish. My guppies seem to be his most recent target. I was told these fish work great with others so I'm wondering if I get him a female will this brutal behaviour stop? I have just recently lost one of my guppies, another one is now hiding in corners and a couple other fish have chunks missing out of their tails. I don't want to buy a whole other tank just for him or kill him but I don't want to lose my other fish from stress cause of his bullying. Any advice would be appreciated.