How many goldfish in a 20 gallon tank?

[BoCoMo]

another vote for zero

 

[platytudes]

The pic you provide looks like some big goldies in what I would guess to be a 55gal or 75gal. Look how close it is to the bottom and how much room is left for him to get to the top.

I guess that's possible. I should revise that statement to say that I have personally never seen a goldfish develop colors and size like that in a mere 55. Perhaps this is a pond fish that is overwintering, or maybe they can be kept as well as that in a tank that size...my personal opinion is "probably can't be" but I can't say for sure, I am no expert on the matter.