Welcome to AA!!
Depends on how big the fish is .... the general guide for feeding is an amount the size of the fish's mouth (or eye). Goldies are such pigs that they will stuff their mouth with however much you give them, to the point that they can't chew/swallow. So 10-12 pellets might be a bit much for a smallish fish. <Eg. I feed about 1/8 teaspoon of Hikari pellets to my 9 1-3" fish ... that is maybe 20 pellets - small size, if you use baby pellets, adjust accordingly (2-3x the number).> Generally, it is better to feed the fish smaller amounts more frequently rather than a single big meal as a Goldie's gut is built for constant grazing rather than big binges. Big meals basically don't get digested & are wasted, plus you risk constipations & gut troubles.
You can feed twice a day (or more - breeders feed every 3-4 hrs, but small amounts) if you want the fish to grow faster. But in a small setup like yours, it will also pollute the water faster & you will need more pwc's to compensate.