A few months ago, a reply to an Ask Metafilter post about goldfish (mildly salty language warning!)
blatantly stated an upsetting fact: the majority of pet goldfish die by drowning in their own... er... urine. Mistakes made by even well-meaning pet owners include overfeeding, feeding the wrong kind of food, putting the fish in a bowl that's too small (goldfish do better in a filtered tank), and not letting water de-ionize for at least a day or two before putting the fish in it (without this waiting period, the goldfish are likely to suffocate). It seems like most goldfish -- even ones loved by the kids who own them -- live short, unhappy lives.
I had goldfish as a kid: since I lived in a small apartment, and my mom hated rodents, goldfish were pretty much the only pet I could
have. There was Frank (named after Anastasia Krupnik'
s goldfish) and, eventually, Spike, who each lived for about a year or two. We thought we did pretty well by Frank and Spike, both won from school carnivals, but as it turns out, the poor little fellas went to an unnecessarily early grave.
The Ask MeFi link is a sad one, but fortunately, I can balance it with a happy one. It turns out that, when given proper care, goldfish can live for at least a decade! Some of the suggestions at WikiHow's wonderful How To Make A Goldfish Live For Decades page
include feeding food made just for goldfish (not generic "fish food"), making sure that the tank has at least 10 gallons of water per fish, and making sure that the tank stays "interesting" for the fish by giving them lots of places to explore that change every month or so.
With these instructions, you can have happy, healthy goldfish for years to come!