petnet learned that one of the most basic conditions for koi to survive is that the feeding water must have enough dissolved oxygen. Under the condition of sufficient dissolved oxygen, koi have a strong appetite, high digestibility, fast growth and active swimming. On the contrary, under the condition of low dissolved oxygen, the food intake and digestibility of the koi decreased, while the respiration rate increased, the energy consumption increased, the swimming was dull, the growth was affected, and the fish experienced gradual weight loss. If the dissolved oxygen in the feeding water continues to decrease (less than 2 mg per liter), the koi will float head due to lack of oxygen, and even suffocate to death in severe cases.

The feeding water of domestic koi, such as river water, well water, tap water, etc., contains high dissolved oxygen, but in the specific environment of small aquarium volume and high stocking density, with The oxygen consumption of carp and the decomposition of planktonic microorganisms, koi excrement, and food residues consume oxygen, and the dissolved oxygen in the feeding water will gradually decrease. During the breeding process, some breeders often think that in an aquarium planted with aquatic plants, the oxygen released by the photosynthesis of aquatic plants is sufficient to meet the oxygen consumption needs of koi. It is far from meeting the oxygen consumption requirements of koi and planktonic microorganisms. When the dissolved oxygen in the feeding water cannot meet the oxygen consumption needs of the koi, the koi respond by floating to the surface and sucking and spitting. At this time, if you do not change the water or artificially add oxygen, and let it float, the koi will soon suffocate and die due to the desire for oxygen. To insist that the feeding water has a high dissolved oxygen content, in addition to frequent cleaning and water changes, the following measures can also be taken: 1. Appropriate stocking density; 2. Individuals with less enlarged body size should be properly planted with aquatic plants or some planktonic microorganisms such as green Algae. The larvae still use the nutrients in the yolk sac to maintain their developmental needs within three or four days after hatching. When the nutrients in the yolk sac are absorbed, the digestive system has been initially fully developed, and the larvae begin to swim and forage. At this time, it should be given to the slushy water according to their appetite (the slushy water is the most suitable bait for koi larvae). If the slush water is insufficient, it can be fed to the boiled duck yolk or egg yolk, crushed and fed in small amounts to avoid affect water quality. While feeding the water or cooked egg yolk, a small amount of live fish and insects should be put into the breeding tank (pool) to make them swallow the dirt in the water to improve the water quality. In this way, after seven to ten days of feeding, the larvae gradually grow up and their swimming ability is also enhanced, so they can be fed with slightly larger small fish and insects or artificial pellet bait.