Due to variations in koi varieties, sizes, rearing environments, and management conditions, different feeding methods must be adopted. When feeding, the characteristics of the feed—such as its source (live feed or artificial compound feed), pellet size, composition, density, and palatability—must be considered based on the size and species of the koi. Feeding amount and frequency significantly impact growth rate and feed utilization efficiency. Additionally, the type of feed used (floating or sinking, pellet or dough, etc.) and feeding methods should be determined according to specific conditions. It can be said that feeding practices are just as important as meeting nutritional requirements.
1. Timing of First Feeding and Feed Types
Newly hatched fry rely on their yolk sac as a nutrient source. After about 2 days, the yolk sac is absorbed, and the fry begin to ingest exogenous nutrients. For artificially hatched fry, initial feeding can start as soon as they open their mouths, but the best results are achieved by mixing live feed such as plankton and Tubifex worms with compound feed. The fry undergo an adaptation period to artificial feed during this time. Around 30 days later, as the fry become more accustomed to artificial feed, they begin consuming it in larger quantities, facilitating a transition to formulated feed.
2. Pellet Size of Compound Feed
Pellet feed offers high stability, reduces water pollution, and minimizes feed wastage. When feeding pellets, it is easier to observe feeding behavior closely and adjust the amount flexibly. The optimal pellet size increases as the fish grow, but should generally not exceed the diameter of the fish's mouth.
3. Feeding Methods
Feeding methods include manual scattering, feeding from a platform, and using automatic feeders. Manual scattering is labor-intensive and time-consuming but allows detailed observation of feeding behavior and can be used to train fish to compete for food. Platform feeding involves placing feed on a feeding platform for the fish to consume voluntarily, typically requiring feed with good water stability. For slow-feeding species, dough-like feed can be used. Automatic feeders dispense pellet feed in several portions throughout the day based on the total daily ration, saving time and labor. When using automatic feeders, accurately determining the daily feed intake is essential.
4. Feeding Frequency
Feeding frequency refers to the number of times feed is distributed into the water after the daily ration is determined. Recommended frequencies are: fry: 6–8 times/day; fingerlings: 2–5 times/day; adult fish: 1–2 times/day.
5. Feeding Time
Generally, it is best to feed around 10:00 a.m. and 3:00 p.m., avoiding feeding in the evening.
6. Feeding Location
For pond-reared koi, the feeding area should be sunny and free of bottom silt, with a water depth of 0.8–1.0 meters. If a fixed spot near a shelter is chosen and feeding occurs at consistent times, koi will develop a habit and automatically gather for food upon hearing their keeper’s footsteps. Koi can also be trained with music: playing a specific tune before each feeding can condition them to gather at the designated spot when they hear it.
Common feeds include floating and sinking types. Floating feed allows observation of fish competing for food, adding to the enjoyment of koi keeping.
Koi are easily tamed and can be trained to take food from their keeper’s hand. Some enthusiasts even hold feed in their mouths for the fish to take, use bottles for the fish to suckle from, or hold the fish in the air to feed them—demonstrating endless creative and enjoyable interactions.
7. Feeding Training
Feeding training involves conditioning koi to gather at a feeding platform for compound feed. This practice improves the utilization of artificial feed, increases feeding intensity, and simplifies operations such as harvesting adult fish and disease control. If larger koi are stocked in a pond and were trained during the fingerling stage, retraining is relatively easy. If smaller, untrained koi are stocked, training should begin as early as possible.
Many methods exist for training koi. Here is one simple and effective approach: when koi reach about 5 cm in length, fresh minced fish or shrimp paste is placed on the feeding platform every evening. Once the koi are actively feeding, a portion of pellet feed is mixed in. Continuing this for about 10 days usually results in successful training.
Feeding Volume
It is generally advisable to feed koi until they are about 80% full. A common guideline is that large fish should finish the feed within about 30 minutes, and small fish within about 5 minutes. Based on factors such as pond design, fish size, stock density, and water temperature, the required amount can usually be determined within a few days. However, adjustments should be made according to feeding activity if fish are unhealthy (especially if parasites such as fish lice or anchor worms are present), during abnormal weather, or when water temperature drops suddenly, as appetite may decrease. Recently, the trend of raising giant koi has grown. To cultivate giant koi, more feed must be provided, ideally through frequent small meals, while carefully managing based on water quality and the health status of the fish.
