He said that his is a Vetail.Dino said:Gold fish are temperate fish, unlike most of the fish we keep, which are from tropic regions.
They do best in the 60-70 degree F range. So in most cases, a heater is not needed.
How many fish are in the tank and what is your water change schedule?
Several goldfish types are not active fish, such as the lion heads or celectrials.
Hopefully we can find out if there is a problem, and get your fish back on track.