Most pet stores consider goldfish a "disposable fish". They are sold as food for other fish so they only need to stay alive long enough to be taken home and put in for the other fish. They are the "sacrificial" first fish to help cycle a tank. Most of them are bred/raised in such cramped quarters that probably 90 % are dead, dying, or diseased when they get to the pet store. I always wait at least 2 days after a new shipment of goldies come in before I will even look at them. That way they have time to show any signs of illness from being moved into the store. Even then, I watch for a good 30 minutes before I pick which ones I want to take home. If there is any sign of
ICH or other diseases in the tank, I won't buy any. No matter how careful you are, there is still a chance that the goldies history will catch up with it and it will die. Not from inbreeding so much, but from the poor conditions in which it was raised and kept. I have been fortunate and have not lost very many goldies bringing them home. The last time I went, I bought 5 and lost 1. It was the smallest one and I wasn't going to get him, but he was just so gorgeous I couldn't resist. I shouldn't have bought him as he was too skinny (his belly was caved in), too small (only about 1/2 inch long nose to tail tip) and was not very active. I gave in because half his length was tail and he was mostly white with beautiful deep orangey red markings on his back and sides - and red lips. White face and head, but deep red lips. Oh well. Maybe I'll find another one day.