I get asked all the time
" How many flakes should I feed to my goldfish and how often"?
Captive fish are entirely dependent on you for their food, so It should be offered regularly. They are a small animal with a very small digestive track, so 4 small meals a day is better than one. The younger the goldfish the more often you should offer them food in varied form to mimic the way they eat in the wild.
Flake foods are probably the most common type of manufactured diet. flake is great for fry through to goldfish as large as 16cm in aquariums and smaller ponds up to 2000ltrs. I tend to go to pellets for larger ponds for all size goldfish, sinking and floating as they are more easily found and consumed in such large bodies of water.
Flake floats for a very short time and is great for fancy varieties of goldfish as they can suffer from buoyancy disorders, so I avoid giving them food that floats for to long.
Aquarium goldfish should feed throughout the year as the water temperature will be fairy constant. Where as goldfish in ponds will get fed much less in winter as the water cools down. Also goldfish in ponds will source food from the algae growing on the sides of the pond, bugs landing in the pond and microscopic animals living on plants within the pond.
Depending on the climate in your area over winter if your pond goldfish are in water below 10 degrees, you should be feeding a low protein flake or wheat germ once a day at lower temperatures feed less. Only feed what they will consume in a minute over winter. As little as 3 times a week.
In the aquarium, it is best to feed goldfish a pinch at a time. Offering them as much as they will eat in two or three minutes on a daily basis. Initially, healthy goldfish are very keen to feed and will greedily eat the food being offered. As they consume it, however they will gradually become less active and this is the point at which to stop feeding. This will avoid overfeeding and the problems of polluting the aquarium.
Variety, Variety feed them lots and they will thrive!
In addition to commercial diets, goldfish appreciate the occasional treat food. Natural foods are the best choice as treat foods
I use fresh lettuce attached to the side of the tank with a plastic clip, I leave it there for a few hours in a day for them to graze on.
Or fresh orange, cut off the skin and white fibres, cut into strip and attach to a rock at the bottom of the aquarium with a rubber band, leave for a few hours for the fish to graze on.
aquarium plants are great also and they can stay in the tank. I pot them in small black pots of aquarium gravel and leave them for them to eat, when they are half eaten I take them outside and put in water for them to continue to grow, so the fish have them to eat for another day.
Always store supplies of manufactured flake in dry conditions in an airtight container.