I have a comet goldfish, about 7 inches long. We've had him for upwards of 5 years. As he has increased in size, and I in knowledge, he has moved from a bowl to a 10 gallon, and now a 20 for the past couple of years.
I know goldfish are quite the dirty fish, so I am currently researching many aspects needed for his proper care in earnest now. One tidbit I'd like an opinion on is just basic tank size for this size of fish, as I gather the inch for inch of fish rule isn't a very accurate way to guage this.
Thanks for any opinions on this.