No flaming please! I have 2 goldfish (bog standard not fancy) in a 60l biorb (I know, I know) What I want to know is, if one of them dies, what am I best doing with the other - can he live alone? They are both maybe 7-8 years old now, and one is going more silver as the years go on
They can live for years, Dh's grandparents had one for 22 years. We had two at first, one died. We were worried about telling ds, he was about 5 or 6, he just shrugged and told us to get another, so we got two tiny red and blue things, can't remember what they're called but goldfish is happy with his new tank mates. We've had them around 2 years now and goldfish for about 3.
No flaming! It's hard to get accurate info on fish care, you really have to go looking for it.
Goldfish can live alone. If you're not going to upgrade the biorb (and I strongly recommend you do, it's not even big enough for one goldfish) then it would be better for the health of the remaining goldfish to be alone because the filter and tank will not be able to support 2 goldfish for their expected lifespan.
Have a look here for recommended tank sizes and a goldfish growth chart.