Could you post a picture? And what are the specs for your filter? And how deep is your gravel? And are there any live plants in the tank?
(Dh doesn't recommend cycling the tank - he says it's hard on the fish. His first guess is that it's too many goldfish for the size tank - that goldfish need 10 gallons *each* (they are really dirty fish
) - but you could probably get by with a bigger filter. But seeing the tank and knowing exactly what sort of filter and such will help pinpoint the issue.)