Feeding Your Koi and Goldfish: The Dos and Don’ts

Feeding your koi and goldfish is one of the most enjoyable tasks for hobbyists. It’s a great opportunity to interact and create a bond with your pond population. Aside from being fun, proper feeding is also one of the best ways to keep your koi and goldfish in great health.

Though feeding may seem like a simple enough task, there are several considerations to take into account. It is far too easy to make mistakes when feeding, some of which can be detrimental to the health of your koi and goldfish. To properly care for your fish, it’s important to make sure you know when, what, and how to feed them. We’ve put together this list of feeding dos and don’ts to help guide and improve your feeding routine and technique.

Don’t

✗ Overfeed

When it comes to both frequency and quantity, overfeeding is one of the most common mistakes. The biggest issue with overfeeding is that it results in your fish not properly digesting their food. This leads to excess waste, which will negatively impact water quality. It also can harm the function of the liver and other organs, which can lead to health issues.

Your koi and goldfish should be fed no more than three times per day. In terms of how much food to give your fish, we recommend using the five-minute feeding method. Give your koi and goldfish a small amount of food. Once they’ve eaten it all, give them a little bit more. Continue this process for a total of five minutes, and then stop feeding. Skim any uneaten food from the water after five minutes.

✗ Underfeed

Though not as common as overfeeding, underfeeding your koi and goldfish can also cause issues. In colder temperatures, when the metabolism of koi and goldfish naturally slows, underfeeding typically isn’t a problem. However, in warmer temperatures, underfeeding can be extremely dangerous.

In the spring and summer months, your fish can grow up to 0.5-1” per month. Lack of growth is one obvious sign of underfeeding. Other signs and symptoms include a thin body, sunken stomach and eyes, dull coloring, lethargy, and rapid weight loss. Follow the five-minute feeding method above to ensure you’re not underfeeding your koi and goldfish. 

✗ Let Uneaten Food Remain In The Water

A problem that often comes along with overfeeding is that some food may go uneaten and remain in the pond. When uneaten food is left in the water, it will start to break down and negatively affect water quality. Ammonia and nitrite levels will rise, and dissolved oxygen levels will lower. Leftover food can also clog your pond’s filter and cause it to not function as effectively.

The best way to prevent these issues is to simply avoid overfeeding. However, if you accidentally give your koi and goldfish too much food, simply use a pond skimmer to scoop out any lingering pellets.

✗ Feed In Cold Weather

The metabolism of koi and goldfish becomes slower when temperatures drop, which makes it much more difficult for them to digest food. While feeding frequency should fluctuate based on water temperature, you should completely stop feeding your koi and goldfish once water temperatures are consistently below 50°F.

Koi and goldfish are cold-blooded, so their body temperature, along with activity levels and metabolism, is regulated by the temperature of the surrounding water. At low temperatures, your fish will go into a state of inactivity known as torpor, which is akin to hibernation. Torpor makes digestion extremely difficult. If koi and goldfish are fed during this time, it can be detrimental. Though it may feel wrong to deprive your fish of food for several months, your fish will not starve. Torpor is completely normal and healthy for koi and goldfish.

✗ Make Sudden Changes In Food

The dietary needs of your koi and goldfish will change throughout the year, which means you’ll need to change up the type of food you’re feeding them. Or, sometimes, you might just be interested in trying a new brand or formula.

Regardless of the reason for changing food, it’s important to make the process gradual. Switching food too often or too suddenly may cause your fish to stop eating. When switching to a new food, start by mixing small amounts with the old food. Do this for 7-10 days, adding a little more of the new food and a little less of the old food each day until you are fully switched. This will allow your koi and goldfish to slowly get accustomed to their new diet.

✗ Feed Before A Big Storm

If the forecast is calling for a storm, do not feed your koi and goldfish. If you are preparing for a larger storm, you can stop feeding as early as two to three days before it’s expected arrival. There’s a couple of reasons for this. The first is that oxygen levels in the air drop when it rains. Your fish need more oxygen when digesting food. When the oxygen levels in the air decline, the water in your pond does not receive as much oxygen as it normally does. The second reason, particularly if you are expecting a large storm or hurricane, is that power outages from storms may interrupt the filtration process. If your koi and goldfish have been recently fed when a power outage occurs, ammonia can quickly build up and negatively impact water quality. By halting feeding, you can help keep the water quality in good shape for longer in the event that the filtration system is impacted by the storm.

Do

✔ Choose A Food Specifically Designed For Koi and Goldfish

When choosing food, be sure to choose a formula specifically made for koi and goldfish. The reason for this is that different types of fish have different nutritional needs. Foods made for other types of fish will likely lack the necessary nutrients that help keep koi and goldfish healthy. If your koi and goldfish have a poor diet, it can stunt growth and lead to stress and illness. We recommend Blue Ridge Koi & Goldfish Food.

✔ Feed Your Koi and Goldfish A Nutritionally Balanced Diet

You are what you eat, and that goes for koi and goldfish, too. Keeping your koi and goldfish healthy starts with a nutritionally balanced diet. When choosing food for your fish, be sure to choose a high-quality feed that is high in protein and vitamins. Stay away from low-quality food, as they typically lack essential nutrients and are high in carbohydrates and fat. Ingredients to look for include spirulina and vitamins A, B, C, and D.

✔ Adjust Feedings Depending On Temperature

Water temperature is one of the most important factors that influences feedings as the metabolism of your koi and goldfish is tied to temperature. Their metabolisms speed up in warmer water and slow down in cooler water. Because of this, it’s essential to adjust the type of food you give your fish when seasons change.

Koi and goldfish can be fed a regular, all-season formula when temperatures are above 65°F. When water temperatures are below 65°F but above 50°F, you’ll need to switch to an easily digestible food. Wheat germ-based formulas are the most popular choice, like Blue Ridge Cool Water Wheat Koi and Goldfish Food. As we mentioned before, you should stop feedings completely when water temperatures drop below 50°F.

Water temperature also plays a role in determining the frequency of feedings. Koi are more active when water temperatures warm up. When temperatures are consistently above 70°F, koi should be fed three to four times per day. One to two times daily is appropriate for temperatures between 62°F and 70°F, and once a day or once every other day when temperatures are between 50°F and 62°F.

✔ Stick To A Feeding Schedule

While your koi and goldfish will digest food easiest when water temperatures are warmest, which usually peaks around midday, this isn’t always the most convenient time for hobbyists given work schedules and other life obligations.

The time of day you feed your fish is not too much of a concern, but the important thing is that you stick to a schedule. Whichever times of day you choose for feeding, make it the same each day. Consistency is key in developing a feeding schedule. Your koi and goldfish will become accustomed to their feeding routine, and it could impact their health and growth if their schedule fluctuates too much.

✔ Give Your Koi and Goldfish An Occasional Treat

A healthy diet is important, but that doesn’t mean you can’t give your koi and goldfish a treat every once in a while. One of the most popular choices are worms, including freeze-dried silkworm pupae, bloodworms, and earthworms. Certain human food can also be used as acceptable treats for your fish, like bread, cheerios, grapefruit, watermelon, and oranges. Just remember that excess sugar and starch isn’t good for your fish, but the occasional treat won’t hurt.

Every pond is different, and each hobbyist develops his or her own feeding techniques, tricks, and tips. But if you keep these dos and don’ts in mind as you establish a feeding routine for your fish, you’ll already be off to a good start. Happy feeding!