How can you know how old is your goldfish?

Answer 1

Underweight: the head will be wider than the fishes body Overweight: the fishes body will have a disproportionally large pot belly (please note that certain kind of fancy goldfish such as ranchu, pearl scales and lionhead naturally have a pot belly)

Answer 2

You simply look at it and compare it to other fish that you have seen. Bloat is usually accompanied by the fish being unstable in the water. If the fishes scales are sticking out like a rasp/file the fish has Dropsy which is a terminal, uncureable disease usually caused by bad water conditions.

Answer 3

It's not that easy to tell the age of a goldfish after awhile. You may be able to get a general guess if you are the original owner and have an idea of when you bought the fish, but otherwise it's too difficult to say for sure.

Answer 4

To know how old your goldfish is, you would need to know when it was born. You can take it to a pet store and have them guess, but it may not be accurate.