Quick answer: goldfish are omnivores. Their everyday food should be a flake, pellet or stick made for goldfish, or a floating pond food in a pond, given one to three times a day and no more than they finish in two to five minutes. Small extras such as peas, daphnia and bloodworm add variety. Do not use tropical flakes as their regular food, and in a pond feed less as the water cools: the Ornamental Aquatic Trade Association says that below 8°C it may be better not to feed at all.
We do not sell goldfish, or a goldfish flake or pellet, but several foods on our dry goods shelf are the extras goldfish keepers use, and our pond sticks are a floating food made for pond fish. This guide covers what goldfish eat, how much and how often to feed them, what changes in a pond, and the richer treats that suit koi and other large pond fish.
What Goldfish Eat in the Wild
In the wild, goldfish (Carassius auratus) feed mostly on and near the bottom, taking plants and algae, decaying plant matter, insect larvae such as midge larvae, other small invertebrates and plankton. Young fish take more of the tiny animal plankton and insect larvae. Goldfish lean further towards plant food than many tropical fish do, and foods made for them reflect that.
The Everyday Food
Feed a food made for goldfish. The Ornamental Aquatic Trade Association (OATA), the UK trade body for the ornamental fish industry, recommends a good flake or pellet in a tank and says goldfish need more carbohydrate than other species, so a specialised goldfish food is the one to buy. The RSPCA advises against buying tropical fish flakes for goldfish, because the nutrient levels differ. Practical Fishkeeping puts typical pond foods at around 25 per cent protein against about 45 per cent for tropical foods, which can carry nearly twice the fat.
In a tank, keep to that goldfish food and use the peas, daphnia and bloodworm below as extras. Some fancy goldfish, the shorter-bodied, twin-tailed kinds, take in air when they feed at the surface and briefly lose buoyancy afterwards; OATA suggests trying a different food or a slow-sinking one if yours do.
How Much and How Often
Small feeds, and less than you might think. The RSPCA suggests two or three small feeds a day, each no more than the fish eat in two to five minutes; OATA says once a day is enough, and Practical Fishkeeping suggests one or two small feeds. All three agree on the amount: what goes in a few minutes, and no more. The RSPCA adds that underfeeding is safer than overfeeding, because fish suffer more from poor water than from a light meal. Food the fish leave rots and adds ammonia, which is toxic to them, so net out anything left and give less next time.
Single-tailed and twin-tailed goldfish are best kept apart: the RSPCA notes that the slower twin-tails miss out at feeding time.
Peas and Other Vegetables
"Goldfish love chopped vegetables such as peas and spinach," says the RSPCA, and OATA suggests thawed, shelled peas and blanched lettuce as extras for fancy goldfish. Our freeze-dried garden peas are one ingredient, garden peas, with nothing added. Soak a few in a little water until they soften, pinch off the skins and squash the soft centres into pieces small enough to swallow. Offer them a few at a time as an extra, not instead of goldfish food, and net out what is left.
Daphnia and Bloodworm
Daphnia and bloodworm make good treats in small amounts. The RSPCA lists water fleas (daphnia) and brine shrimp as a supplement for tropical fish and says to give goldfish only small amounts of them, because they are high in protein, and OATA names daphnia, bloodworm and brine shrimp among the extras for fancy goldfish. Our dried daphnia are whole, freeze-dried water fleas at 50 per cent protein, and our freeze-dried bloodworm are midge larvae at 55 per cent. A small pinch, eaten within a couple of minutes, is the right size for a treat. Our guide to what daphnia is has more on the water flea itself.
Goldfish in a Pond
In a pond, goldfish find some of their own food among the plants and insects, and most keepers feed them as well through the warmer months. OATA says pond goldfish may prefer a balanced floating food, and a floating food lets you see what is left. Our Pond Sticks Mix is a floating stick of wheat, soya, wheat germ, spirulina and paprika, at 18 per cent protein.
Feed pond fish by water temperature, not the calendar, and keep a thermometer in the water. OATA's advice is a higher-protein food in summer and a lower-protein food, such as a wheatgerm food, as the water cools, and it says that below 8°C it may be better not to feed at all; one food maker rates its wheatgerm food for water down to 5°C. In spring, start again slowly as the water warms: little and often, says the RHS, and slowly enough, says OATA, for the bacteria in the pond filter to catch up. Over winter, the RSPCA advises keeping a hole in any ice by standing a pan of hot water on it rather than breaking it.
Treats for Koi and Larger Pond Fish
Koi are omnivorous carp, and their everyday food is a pond pellet or stick sized to the fish. For koi and other large pond fish, a few richer foods make warm-weather treats. Silkworm pupae are commonly used as fish feed in Japan and China, and our dried silkworm pupae are whole pupae at 27 per cent fat, so keep them occasional. Our dried shrimp are whole, sun-dried shrimp, and our dried calciworms are dried black soldier fly larvae; both listings name koi among the fish that take them. Give treats a few at a time when the fish are feeding well in warm water, and keep the bags sealed somewhere cool and dry, because the fat in rich foods goes rancid if they are stored badly. For goldfish, keep to the smaller extras above.
What Not to Feed Goldfish
- Tropical flakes as their regular food. They are made for warm-water fish and are richer in protein and fat.
- More than they finish in a few minutes. Leftovers foul the water.
- Large amounts of rich foods. Daphnia, bloodworm and other high-protein foods are treats for goldfish, in small amounts.
- Meat and dairy. Practical Fishkeeping advises keeping animal meat and dairy fats out of a fish's diet; plain vegetables are the kitchen foods to use.
- Holiday feeding blocks. The RSPCA does not recommend them: they release a lot of food quickly, and much of it can rot.
Going Away
The RSPCA asks for someone to check the fish and their equipment every day while you are away, with instructions on how to feed them without overfeeding. We found no UK welfare body that gives a number of days a goldfish can go without food; Practical Fishkeeping's holiday advice, written for aquarium fish in general, is that around five days is safe for healthy, well-fed fish. Whatever the length of the trip, measure each day's food into its own small bag for your fish-sitter, so a well-meant extra pinch does not end up fouling the tank.
Frequently Asked Questions
What is the best food to feed a goldfish?
A flake, pellet or stick made for goldfish as the everyday food, or a floating pond food in a pond, with small extras such as peas, daphnia and bloodworm.
What should you not feed goldfish?
Tropical flakes as their regular food, large amounts of protein-rich foods, meat and dairy, and more than they finish in a few minutes.
How many times a day do goldfish need to eat?
One to three times a day. The RSPCA suggests two or three small feeds and OATA once a day; whichever you choose, give only what they eat in a few minutes.
How long can a goldfish go without food?
Practical Fishkeeping's holiday advice for aquarium fish is that around five days is safe for healthy, well-fed fish, but the RSPCA asks for someone to check the fish and their equipment every day you are away, so arrange a fish-sitter with pre-measured portions.
Can goldfish eat peas?
Yes. Soften them, pinch off the skins and squash the centres into small pieces, then offer a few as an extra.
What human foods can I feed my goldfish?
Plain vegetables such as peas, spinach and blanched lettuce. Leave meat and dairy out.
Can goldfish eat tropical fish food?
Not as their regular food. The RSPCA's advice is not to buy tropical flakes for goldfish, because the nutrient levels differ, so feed a food made for goldfish.
Should I stop feeding pond fish in winter?
Feed less as the water cools. OATA says that below 8°C it may be better not to feed at all; start again slowly in spring.
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