How to Raise Koi Fish So They Grow Fast? Practical Breeding Tips Shared

Koi fish is a high-end ornamental fish popular around the world today, with a robust build, brilliant colors, varied patterns, and a majestic swimming posture. It has the reputation of being a living gem in the water and a swimming work of art. It is gentle by nature, likes to swim in groups, is easy to raise, and is highly adaptable to water temperature, able to live in water environments of 5-30°C. Let's take a look below at how to raise koi fish so they grow fast!

What Kinds of Feed Are There for Koi Fish?

1. Animal feed: Animal feed is one of the foods koi love most and is the most nutritious, with a very large variety. Common ones include fish insects (bloodworms, water fleas), cyclops, paramecium (gray water), mosquito larvae (chironomid larvae), and tubifex worms.

2. Plant feed: Animal-based feed is the most ideal for koi, but when animal-based feed is lacking for various reasons, plant feed can serve as an emergency or life-sustaining supplementary feed. Common ones include duckweed, aquatic plants, and so on.

3. Synthetic feed: Koi synthetic feed is artificially formulated according to the growth needs of koi, with complete nutritional components that meet the needs of koi growth and development. The main components include 5 major categories: protein, carbohydrates, fat, inorganic salts, and vitamins.

How to Select Koi Fish

1. Health: No matter what kind of fish you buy, choose ones that swim agilely, eat actively, have a well-proportioned and robust body, broad shoulders, thick lips, and a powerful caudal peduncle. Regardless of anything else, as long as the fish is healthy, the raising process will certainly reduce the troubles of disease.

2. Body color: Whether a koi has excellent genes is most directly reflected in its body color, and the requirement for koi body color is only that it be deep and vivid. White should be pure and warm, red should be vivid as blood, and black should be dense but not scattered.

3. Patterns: The patterns of koi already have clear requirements for different varieties. For example, the red should not pass the nose and should not go below the eyes; Taisho Sanke's black should not appear on the head; Showa must have menkui (facial markings), and so on.

4. Body shape: The body shape of koi should be smooth. Only with a good body shape can there be a good swimming posture. Generally, first look at the head, then at the performance of the koi's tail, and finally at the overall performance of the koi's body.

Feeding Methods for Koi Fish

1. Body growth: When the water temperature is above 30°C, feed no more than 2 times per day. The water body should be protected from direct sunlight to prevent water temperature from rising. When the water temperature is 20-30°C, feed 2-4 times per day. When the water temperature is below 20°C, it is recommended not to use body-growth feed.

2. Color enhancement: When the water temperature is above 30°C, feed no more than 2 times per day. The water body should be protected from direct sunlight to prevent water temperature from rising. When the water temperature is 20-30°C, feed 2-4 times per day. When the water temperature is below 20°C, it is recommended not to use color-enhancing feed.

3. Growth development: When the water temperature is above 30°C, feed juvenile fish no more than 4 times per day and adult fish no more than 2 times per day. The water body should be protected from direct sunlight to prevent water temperature from rising. When the water temperature is 20-30°C, feed 2-4 times per day. When the water temperature is 15-20°C, feed 1-2 times per day.

4. Germ: When the water temperature is above 30°C, feed juvenile fish no more than 4 times per day and adult fish no more than 2 times per day. The water body should be protected from direct sunlight to prevent water temperature from rising. When the water temperature is 20-30°C, feed 2-4 times per day. When the water temperature is 15-20°C, feed 1-2 times per day.

5. Staple food: When the water temperature is above 30°C, feed juvenile fish no more than 4 times per day and adult fish no more than 2 times per day. The water body should be protected from direct sunlight to prevent water temperature from rising. When the water temperature is 20-30°C, feed 2-4 times per day. When the water temperature is 15-20°C, feed 1-2 times per day.

How to Raise Koi So They Grow Fast?

1. Water quality management: Koi are not strict about water temperature and water quality and are suitable for living in slightly alkaline water with low hardness. But as the saying goes, “to raise fish, first raise the water,” so do not underestimate water quality. You should know that most koi diseases are caused by poor water quality.

2. Water temperature management: The water temperature range for koi is 2-30°C, and the most suitable water temperature is 20-25°C. In water at this temperature, koi swim actively, have a strong appetite, are robust, and have vivid colors.

3. Rearing density: When raising koi, pay attention to density. Generally, a 60×30×15 cm aquarium can keep 6 koi with a body length of 15-20 cm, a 90×30×50 cm tank can hold 8, and a 110×30×50 cm tank can hold 10.

4. Bait feeding: Koi are similar to goldfish in terms of rearing. They can be fed twice a day, and the amount of bait should be increased or decreased according to temperature in different seasons of the year. Generally, you can feed fish insects, pellet feed, small earthworms, and other bait, but do not feed too much; generally about 80% full is enough.

5. Fish disease prevention and control: Common koi diseases include saprolegniasis, gill rot disease, enteritis disease, and dropsy, among others. Pay attention to applying corresponding drugs to improve the situation. Although koi diseases are unavoidable, it is still recommended to do a good job in preventing koi diseases.

6. Four-season management

① Spring: The weather is warm at first and then turns cold again. Koi begin to revive from winter dormancy and should be moved from indoors to outdoors, but pay attention to sudden temperature drops, cover with plastic film in time, and keep the water temperature stable. Feeding should mainly be plant-based bait, and the amount should gradually increase from small amounts.

② Summer: The weather is hot and scorching. A plastic shade net must be added to prevent direct sunlight, so that the sunlight illuminance is reduced from 8000-12000 lux to 5500-5800 lux, which is most suitable.

③ Autumn: The weather has little rain and is mostly sunny, and the water temperature drops noticeably. This is the most suitable time for koi growth. You can increase the proportion of animal protein, such as silkworm pupae, and increase the feeding amount to promote fast growth.

④ Winter: The weather is relatively cold. When the air temperature drops to 0°C, koi should be moved indoors in time to overwinter in an indoor fish pond. The indoor water temperature should be maintained at 2-10°C, with appropriate feeding to preserve body condition and prevent disease.

Koi Disease Prevention and Treatment Techniques

1. Koi saprolegniasis

[Symptoms]A layer of white hair grows on the fish body. If not treated in time, when the pathogen invades the body, the fish will gradually weaken and die. When it parasitizes the gills, it forms gill mold disease, often causing explosive death.

[Prevention and treatment]① Wash with 1.5-2.5% salt water, remove the hair-like substance, then apply 2% red medicine, and then bathe with fish terramycin. ② Apply a 0.1-1% concentration malachite green aqueous solution to the wound and the area where saprolegnia is attached. ③ Soak the fish body for 3-5 minutes in a 1:15000 malachite green aqueous solution. ④ Soak the fish body for half an hour in a 10 mg/kg potassium permanganate aqueous solution.

2. Koi enteritis disease

[Symptoms]The anus is red and swollen, and the intestinal tract is congested and inflamed. In severe cases, the fin base is congested, red spots appear on the abdomen, ascites flows out when the abdomen is cut open, and the entire intestine is red or purple.

[Prevention and treatment]① Sprinkle bleaching powder at 1 mg/kg over the whole pond. ② For each hectare with a water depth of 1 m, sprinkle 225-375 kg of quicklime over the whole pond. ③ For every 10 kg of fish, use 1 g of sulfaguanidine to make medicated bait and feed it. ④ For every 10 kg of fish, use 50 g of garlic to make medicated bait and feed it once a day for three consecutive days. ⑤ For every 10 kg of fish, use 50 g of dried humifuse euphorbia herb to make medicated bait and feed it once a day for three consecutive days.

3. Koi dropsy

[Symptoms]The body surface of the diseased fish is rough, the scales stand upright, and the appearance is pinecone-like. In severe cases, the eyeballs protrude, breathing is rapid, the back turns over, and eventually death occurs. The scale sacs are edematous, and transparent or blood-containing exudate accumulates inside. If slight pressure is applied to the scales, liquid will spray out from the scale sacs. The diseased fish sinks to the bottom or loses balance, with the abdomen facing upward, and finally dies of exhaustion.

[Prevention and treatment]① Prevent the fish body from being injured. ② The broodstock spawning pond should be dried in winter and disinfected with quicklime or bleaching powder. ③ Add 5% crude chlortetracycline or oxytetracycline to the feed and feed it. ④ Orally administer vitamin E. For every 10 kg of fish body weight, use 0.3-0.6 g per day for long-term use. When diseased, increase to 0.6-0.9 g (for 10-15 consecutive days) as an auxiliary therapeutic drug.

4. Koi white skin disease

[Symptoms]Koi white skin disease is caused by Pseudomonas dermoalba. The skin from the rear part of the dorsal fin to the base of the caudal fin turns white, appearing like white mist. When touched by hand, the scales are rough and lack mucus. Diseased fish near death often have the head downward and the caudal fin upward in an inverted position.

[Prevention and treatment]① Be careful during handling to prevent injury to the fish body. ② Soak the fish body for 30 minutes in 12.5 mg/kg chlortetracycline or 25 mg/kg oxytetracycline. ③ Sprinkle 1 mg/kg bleaching powder or 2-4 mg/kg gallnut over the whole pond.