a little while ago my little brother got into my betta fish tank and tried and failed to "hold him" well then my fish just kind of sank to the bottom of the tank breathing really heavily, its happened before but i was worried because it looked like he was suffocating so i put some of his tank water in a container and then put him in it, which was probably not the best idea but if he was going to die anyway then it didn't really matter, well he started doing much better when i did so it must have been the right thing to do, anyway while he was in there he wasn't eating and then his tail started falling out. eventually his whole tail had fallen out and then he began to eat again so I put him back into the tank and he is doing fine now his tail is even starting to grow back. I would just like to know why his tail fall out like that.