Well my moms goldfish have survived thorugh everything they are VERY hardy. So about three weeks ago one of my moms goldfish jumped straight out of the tank. I have been telling her for months now to get a lid for the tank. Anyway the goldfish was on the floor and my dachshund Hollie found him and barked @ my mom. Well my mom put him back in the tank. Well about two days later his tail rotted off and he wasn't doing so good. So I added some Melafix to the tank every three days. Well her got better. And now his tail is growing back.