You should feed them once or twice a day and give them as much as they can eat in 3-4 minutes. Pinches are not a good measure as my pinch sized portion might be really different than yours.
BTW, fishes is most certainly a word, but the correct word for your question is Goldfish, not gold fishes. Fishes refers to several fish or all different types. A tank with a platys, a goldfish, and a cory catfish: It is perfectly correct to say "Look at my fishes" or "I have 3 fishes" A tank with 3 goldfish, you would say "Look at my 3 fish."
MM
