A: Technically, yes. Koi aren’t picky and they will happily gobble up goldfish food. That being said, there’s a difference between can and should.
Goldfish and koi are both types of carp, and they can thrive in similar conditions. There isn’t much you need to change about a goldfish pond to make it suitable for koi, and the two fish can even co-exist peacefully. There are, however, some notable differences. Koi are larger and they have downward-facing jaws with barbels, while goldfish have forward-facing, rounded jaws.
These physical differences translate to different dietary needs. Koi fish food tends to have more protein than fish food pellets intended for goldfish. The higher protein content is necessary due to the koi’s size and activity level. Koi pellets are usually smaller, as well, to accommodate the unique design of a koi’s mouth.
Goldfish food won’t harm your koi, but more suitable options exist.
Warm Weather Feeding
When the water temperature of your pond is above 50 degrees Fahrenheit, koi require a protein-rich diet. During warmer months, koi should be on a daily feeding schedule. To avoid a build-up of algae and debris, feed your koi only what they can consume in a five-minute period.
There are many types of food you can choose from during this time. For solid, everyday options that will contribute to your koi’s overall health without breaking the bank, you can’t go wrong with either The Pond Guy’s Staple Fish Food or TetraPond Variety Blend Fish Food. These foods are also suitable for goldfish, making them ideal for mixed-fish ponds.
Certain foods can really help your koi’s colors pop. Both TetraPond’s Koi Vibrance Fish Food and The Pond Guy’s Growth & Vibrance Fish Food are designed to enhance your fish’s colors and support maximum growth.
For those interested in competing in fish shows or simply having the absolute best-looking koi around, it’s best to use show-grade options such as CrystalClear’s Platinum Standard Pellet Fish Food and Hikari’s Hi-Growth Fish Food. These foods are formulated to support rapid muscle growth and vibrant colors, as well as improve a koi’s overall gloss and luster.
You may be wondering, other than pellets, what do fish eat? Treats, of course. For that, there is Hikari’s Silkworm Selects.
Cold Weather Feeding
When water temperatures are between 40 and 50 degrees Fahrenheit, opt for a wheat germ-based food such as The Pond Guy’s Spring & Fall Fish Food. A koi’s digestive system slows down at cooler temperatures, and wheat germ is easier for them to digest. You can also switch to a three times-per-week feeding schedule.
If water temperatures dip below 40 degrees Fahrenheit, koi enter hibernation. Do not feed koi during this time. Their digestive systems slow to a crawl, and they are able to survive based on their existing fat stores. Giving koi food in this state can cause more harm than good.
While koi and goldfish can eat the same food, koi really do best on a more specialized diet. Foods tailored to a koi’s dietary needs will help increase color vibrancy, support muscle growth, and keep your koi healthier longer.