The proper fish/water ratio if I'm not mistaking is one fish per gallon if water, so 35 fish to 35 gallons.
How many small common goldfish can go in a 35g tank?
The one fish per gallon is not true and doesn't work for lager fish. You wouldn't put a 12 inch goldfish in a 12 gallon tank. Or at least you shouldn't. But you could probably put 6-12 4 inch goldfish in the tank but coomon goldfish grow fast and pretty soon thoose goldfish will need about 50 gallons of water just for 1 fish. So a pond would be better for thoose fish.