Damaged tails can grow back, just slowly and not to the full prettiness as the original. I had a female betta (she passed on, was old) who somehow messed up her tail. I don't know how, could have been bullying but I'm not sure because the fish don't really bully others from what I've seen. I then moved her into a tank with other female bettas, and that was fine, no fighting.. Anyways, the tail was slowly healing when she left the tank.

I do not feel bad taking my time at a fish store to pick out the ones I want. It is my money, and I want the best quality product. More importantly, I want my new pet to be in good condition so I can keep them healthy and to have a good life. When I go to a fish store, I take a long time before picking out my new pets, and for a good reason. An unhealthy fish will affect the ones you already own and can carry diseases/infections to them. Always look at each individual fish before buying, no matter how small they are or how many you are getting.