I don't know! Luckily I've only had to do it 4 times, 3 fish and a hamster. After the fish I got Tigger to fill the tank because I couldn't bare not to have a pet. The hamster was PTS because he had a very large cancerous tumor and he was almost 4 so we couldn't opperate. He wasn't even mine though, my cousin gave him to me to take care of when he moved to England. He didn't know how long he was going to live their but he never saw Hammy again, my cousin ended up staying there 5 years.