Especially in summer, every day, just use plastic hose to gently suck the excrement and sundries of koi fish at the bottom of the fish tank together with the old water to remove the dust and floating excrement on the water surface, and then slowly inject fresh water with the same water temperature along the fish tank wall to keep the water clean. This method of changing water is not easy to hurt fish, simple and safe, and is most suitable for family aquarium culture.
2. partially change the water.
This method of changing water is mainly carried out in two situations. In one case, in the hot summer and early autumn, koi fish's water in the fish tank has been changed for several days, but the color of the water soon turns green (mainly due to the small amount of feed). In the case that the water quality is relatively clean, in order to prevent koi fish from scalding his tail, you can fish out all the koi fish in the fish tank and let the water in the fish tank spiral. At rest, the dirty things and old water in the center of the fish tank can be sucked to 65438+ with plastic rubber pipes.
Another situation is that the water in the fish tank has only been changed for a few days, and the color of the water is still good. However, due to excessive feeding and floating head, emergency measures must be taken The method of changing water is the same as that mentioned above.
If it is a big fish pond in a fish farm, it is not necessary to fish out koi fish, but to enclose the fish with a folding screen, and then gently rotate the water in the pond for several tens of seconds. When the water is still for a while, start the drain gate to drain slowly or suck up the surplus fish, feces and old water in the center of the fish pond with a straw, or fish out the surplus fish from the center with a fishnet bag and put it back 1/4-65433.
3. Change the water thoroughly.
This water changing method is often a combination of turning over the jar to select young fish or adult fish. It is often used because the water quality is seriously deteriorated or the moss is too long and the fish is too dense. There are two specific methods:
(1) In the absence of a free pool, we have to fish all koi fish into the pool or put the cage in the water of an adjacent pool for temporary cultivation, and add an aerator to the pool or cage for aeration. Then, brush off the moss on the wall of the original fish tank, rinse it thoroughly, re-inject isothermal new water, let it stand for a while until the water temperature is equal, and then put the fish into the original fish tank.
(2) If there are free pools and fresh water, all koi fish should be fished into pots or cages and treated separately. When the water temperature is equal, koi fish can be moved into fresh water for culture. This method of changing water should pay special attention to the water temperature, and it is best to choose it before 9 am on a sunny day. However, this method is generally only applicable to adult fish or larger young fish, and young fish should not be used. If possible, it is best to fill the spare fish tank with flooded water before completely changing the water, and then fish directly in the spare fish tank. In this way, the water temperature changes little, the fish can easily adapt to the new environment, and the fish can be prevented from being squeezed in pots or cages. In spring and autumn, this method of changing water is generally carried out every half month or so 1 time. In summer, the weather is bad, and the water temperature is as high as 28℃, so it is necessary to completely change the water 1 time in 5-7 days. When the water temperature drops to about 4℃ in winter, the activity of koi fish is slow, the appetite decreases, and the water quality is not easy to deteriorate. Generally, the water is not completely changed unless there are special circumstances.