What Do Pond Fish Eat? A Guide to Natural & Supplemental Feeding 2022
Most common pond fish are omnivorous, and will eat quite an – perhaps unexpected – array of foods if provided. For example, koi and goldfish will eagerly consume peas, citrus fruits, squash, spinach, wheat germ, plankton, blood worms, shrimp, and even algae! However, a fish’s diet does depend at least somewhat on water temperature. In warmer waters (above approximately 60 degrees Fahrenheit), fish metabolism is high and they will need protein-rich foods. In waters below 60 degrees, a diet lower in protein and higher in carbohydrates can also be suitable, such as with fruits and veggies, is more suitable as their metabolisms are significantly lower and they won’t need as much energy as in warmer months.
Here we will discuss the basic dietary requirements of some of the most commonly kept pond fish species – goldfish, koi, and sturgeon – as well as recommend some healthy food choices you can feed your pond fish besides normal pelleted foods.
What Will Pond Fish Eat Naturally?
In a fully natural environment without supplemental food, familiar pond fish species still have a diverse diet and are adept at finding sources of food. Goldfish in particular are known to be opportunistic eaters, and will eat plants such as water sprite and duckweed, crustaceans, insects and aquatic macroinvertebrates (such as caddisfly, mayfly, and mosquito larvae), and tadpoles.
Larger goldfish may also eat fish smaller than themselves, as well as frogs. Wild koi (also known as the common carp, the domesticated koi carp’s ancestor) will readily eat aquatic insects, flies, algae, smaller fish, plants like water lily and water lettuce, snails, and frogs. As bottom feeders, they also browse along the water body’s floor using their maxillary barbels for any live or decaying plant or animal matter that has settled amongst the substrate. Sturgeons in the wild can grow to be massive (around 100 pounds, and over 500 pounds in the case of the Atlantic sturgeon), and it takes a great deal of food to achieve and sustain such a hefty size. Like koi, they are bottom dwellers and rely on sensitive facial barbels to locate everything from clams and barnacles to snails, fish eggs, insect larvae, shrimp, dead fish, and even sizeable fish such as salmon and flounder.
What Can You Feed Koi & Goldfish Besides Pellets? (Healthy Choices)
1) Supplemental Proteins
Quick answer: Brine shrimp, soybean meal, insects, bloodworms, silkworms.
For added nutrition, your pond fish can be fed a multitude of other supplementary foods. Nearly all fish require 10 amino acids (the building blocks of protein), and these can be supplied through protein sources like brine shrimp, bloodworms, silkworms, soybean meal, and naturally occurring insects and worms. Goldfish and koi are able to digest both plant-based proteins and animal-based proteins, but shrimp, bloodworms and the like should be provided in small quantities and are usually considered “treats.” Sturgeon require around 40% of their diet to be composed of protein (obtained mostly from animal sources, contrary to koi and goldfish), and 30% and 35-40% for goldfish and koi, respectively. Younger fish require more protein since they are growing, so supply an additional 5% protein for them.
2) Supplemental Carbs & Sugars
Quick answer: Raspberries, shelled peas, carrots, watermelon, broccoli, cheerios, lettuce and citrus fruits.
Fish also need carbohydrates to supply prompt energy, though not usually in great supply – koi and goldfish are prone to suffer from liver degeneration, often unbeknownst to the pond keeper, as a result of being fed too many carbohydrates. To be on the safe side, keep their diet composed of at or below 10% carbohydrates. Raspberries, wheat germ, shelled peas, watermelon, broccoli greens, citrus fruits, and cheerios (in small amounts, as cereal grains are very starchy for fish) will provide not only carbohydrates, but other necessary vitamins and fiber as well. Carrots and shelled peas (either boiled lightly or ground up) can also help enhance the color of your fish, as can spinach and spirulina (a species of blue-green algae).
3) Supplemental Fats (Lipids)
Quick answer: Brine shrimp, bloodworms, silkworms, krill, fish oils, soy bean meal.
Lipids, or fats, are the main fuel source for energy metabolism in fish muscles, providing as much as twice the amount of energy as protein or carbohydrates, and contain vital fatty acids. Fish with lipid-deficient diets have been found to experience stunted growth, deformities, and other issues. Linseed oil is one of the best types of oil for fish, as it provides an adequate amount of both linolenic and linoleic acids, the two essential fatty acids needed by many common pond species (particularly koi). Aquatic oils (derived from salmon, krill, shrimp etc.) are also an acceptable choice for pond fish. Essential fatty acids should compose around 5-10% of goldfish and koi diets and 10-15% for sturgeon.
Be aware that organisms (terrestrial and aquatic alike!) can develop potentially deadly diseases if they eat too much fat. For example, South Africa and Mozambique’s Nile crocodile populations began to plummet suddenly beginning in 2008 due largely to a fatal disease called pansteatitis that is most closely linked to high polyunsaturated fat intake and low vitamin E levels (among other factors, including poor water quality). This disease has also been found to present itself in fish, turtles, birds, and even domestic dogs and cats for the same reasons.
With this in mind, moderate the fat intake of your pond fish and supplement with a bit of vitamin E to ensure proper cellular metabolism of fats and any toxins that may be present in the environment. Healthy fats, including linoleic acids and vitamin E, can be found in high quality pellet feeds, or in supplemental foods such as brine shrimp, bloodworms, silkworms, krill, or soy bean meal. You can also try making your own fish food so that you know exactly what is going into their food and how much.
4) Supplemental Vitamins & Minerals
Quick answer: Fruits, veggies, proteins, and fats – all of the above contain vitamins & minerals!
Most fish require only small amounts of vitamins and minerals, which can be obtained easily via the food sources already listed (fruits, veggies, carbohydrates, and so on), as well as directly from the water itself via osmotic diffusion. However, iron, zinc, copper, and magnesium cannot be obtained from the water by fish and have to be acquired from their diet, though these are needed in fairly minute amounts and so you likely won’t need to concern yourself with supplying them directly.
The Benefits of Feeding Pellet Foods (Why You Still Should)
To be certain that your fish are meeting all of their dietary needs, it is best to use a high quality pellet feed, though you can provide supplemental feedings now and again of the things listed above, in moderation. Pellet feeds often contain high protein content as well as all of the essential vitamins and minerals that your fish need, so this makes it easy and straightforward to keep track of the exact nutrient types and amounts that your fish are getting. Utilizing pellet feeds helps ensure that your fish will have a well-rounded diet, and in turn will promote healthy growth, decrease the likelihood of disease, and aid in building a strong immune system. Some even have added enhancers to improve color, though it has been argued by some that fish color is more so tied to water quality and genetics than diet.
Regardless, do your research on pellet feeds to make sure that you choose one(s) that meets your specific fish requirements. Also, you may wish to opt for floating pellets as these will help you to monitor how much your fish are eating, and can be easily removed if the pellets are not entirely consumed. Sinking pellets that don’t get eaten will add excess nutrients to your water and can adversely impact water quality, fueling algae growth and depleting much-needed dissolved oxygen in the water. As a general rule, only feed your fish what they can eat in 5 to 10 minutes – don’t be fooled by their continued begging, as you’ll risk overfeeding them and sullying the water quality.
If you have koi, you can also check out our guide to nutrient balanced koi food recipes here!
13 thoughts on “What Do Pond Fish Eat? (Natural & Supplemental Foods)”
DO I HAVE TO REMOVE WATER LETTUCE FROM MY POND IN THE FALL
Unless you live somewhere with very mild winters, or intend to bring water lettuce indoors until spring, it likely won’t survive long after the first frost hits. With that in mind, and since water lettuce is very cheap to re-purchase every year, simply removing it towards the end of fall so it doesn’t contribute to waste can be a good idea to help improve water quality over winter.
Hello😀 …. I have a new established garden pond (startet in march) … it is a “wildlife pond” with many plants, insekts, tadpoles, snails, swan mussels and i have observed dragonflies laying eggs underneath/on plants….. i also have 6 Shubunkin in the pond…. my question is, why du my Shubunkins not eat the floating pellets i give them? … do they feed enough on what the pond provides?
Congrats on the pond! It sounds like your eco-system is truly thriving.
Yes, your shubunkins could very well be getting enough food from the environment, especially if you have an abundance of insects and larvae for them to eat. If they’re looking vibrant, healthy, and not too underweight, I’d say they’re doing just fine and they probably just prefer natural food to the feed you’re using.
A possible way to tempt them to eat pellets would be to try a different feed, as the quality of ingredients between some feeds is extreme (and fish can tell!). You can find some of my recommendation here for good quality fish feeds:
Thank you for your response👍 …. why are my fish so shy ….. they hide under the plants and du not come out if we are pressant …. they have been in the pond for almost 3 weeks now???
Some fish are just shy by nature, whereas others may simply take a long time to grow accustomed to their new environment. A method of getting fish used to your presence is to slowly get closer to the pond each time you feed, so they eventually associate you with food and not danger. You can do this by feeding and then backing away from the water, right up to a distance where they’ll take pellets from the surface. As they feed each day, slowly get closer and closer to the water, making sure to back off a little if they spook. It takes time, but this is actually how I got one of my shy koi used to feeding, and now they literally eat from my hand!
I’ve going on walks next to a creek and I have Noticed There are little fish in (about 3cm long) what could I feed them?
Thanks for reading and commenting!
I would strongly discourage anyone from feeding fish or any other organism in a natural setting. Just as with feeding deer, birds, bears, etc., feeding fish habituates them to people and can actually lessen their chances of survival as the fish will come to expect food to be given to them rather than finding their own. Feeding fish in an ornamental pond is one thing, but nature should not be tampered with. I’m a nature lover, so I can certainly understand the desire to want to be a part of and take care of other creatures! However, in natural settings we must resist this urge and allow things to take their own course.
I do hope that you can appreciate this, and that you continue reading our blogs!
Can I feed my fingerling with supplement food like crumb, small rice or bread??
Unfortunately, crumbs, rices, and breads contain too many carbohydrates for most fish. The fingerlings may be able to tolerate a very small amount on rare occasions, but in general things like bread often cause nutrient deficiencies and constipation as the bread swells up in the digestive tract and makes them feel full, but doesn’t pass through easily. For their low carbohydrate needs, try feeding things like shelled peas, fruits like raspberries and watermelon, and wheat germ. They’ll gobble them up readily and receive loads of beneficial nutrients from them.
Can you suggest me with type of food best for lake fish Raw fish
What type of fish are they?
I’ve had a pond for years, I never fed the goldfish but once I started to notice how much they were reproducing I started feeding them pellet food just to have some more fun interaction. They are really thriving, I have a constant batch of new baby fish. Hopefully most of them make the winter, I live in NJ and the winters have been mild so I started with a good amount of fish this spring (11).
My question is; now that I started feeding them pellet food will they not eat the natural food they have always eaten, do I have to keep feeding them pellet food everyday now? Or will they start to live off of the natural food again?