How do you keep koi fish in winter so they survive the cold safely?

Koi fish are a high-end ornamental fish popular throughout the world today, praised as “living gems in the water” and “artworks that can swim,” and many people like to keep them. So, how do koi fish overwinter?

1. How do koi fish overwinter?

In winter the weather is relatively cold. When the temperature drops to 0°C, the koi fish should be moved to an indoor fish pond to overwinter, keeping the water temperature between 2°C-10°C. Feed bait appropriately to maintain the koi's body weight, and also do a good job of disease prevention and control.

2. What do koi fish eat?

Koi fish are omnivorous fish; generally mollusks, fragments of higher aquatic plants, benthic animals, and even tiny algae or artificial synthetic pellet bait can all be eaten. In artificial breeding, you can feed synthetic pellets, soybean cake, rapeseed cake, bread crumbs, fish worms, clams, crab meat, duckweed, water velvet, and other bait. It is best to feed the bait at fixed times to avoid causing stress reactions in the fish.

3. How do you tell male koi from female koi?

You can look at the body shape: those with a slender body are male, and those with a large, plump belly are female; you can look at the vent: those with a small, sunken vent are male, and those with a wide, flat vent are female; you can look at the breeding stars: during the breeding season, those with breeding stars are male, and those without breeding stars are female; feel the fin rays with your hand: if there are rough, keratinized protrusions, it is a male fish, and if smooth, it is a female fish.