What are the water change requirements during koi carp farming

SummaryWhen the water color and water quality change due to overfeeding or underfeeding, only a partial water change is needed; if the water quality is very poor and the moss in the water is too long, affecting the growth and development of the fish, then a complete water change should be carried out. For a partial water change, you only need to make the water in the tank or pond rotate in a spiral for a while, then drain out part of the old water and add an equal amount of new water at the same temperature; a complete water change, however, requires draining all the water in the tank or pond.

1. Partial water change

It is mostly used for koi carp kept in home aquariums or on farms when too much feed has been given.

For koi carp kept in aquariums, in the hotter summer and early autumn, even if the water is changed frequently, because the amount of feed given is relatively small, the water color in the aquarium will quickly turn green. If the water quality is not suitable and is very poor, you can first scoop out the koi carp from the aquarium, then make the water in the aquarium rotate in a spiral, and after the water becomes still, use a plastic rubber tube to siphon out about 1/3-1/2 of the dirt and old water from the middle of the aquarium.

Then add new water of the same temperature and amount to the tank, and then put the koi carp back in. If too much feed is given on a given day, causing the fish to gasp at the surface, this method can also be used for a partial water change.

If it is pond farming, there is no need to scoop out the koi carp. You only need to use a folding blocking net to pen the koi carp to one side, then use a dip net to gently rotate the pond water for several dozen seconds, and after the water becomes still, immediately open the drainage gate and slowly release the water, or use a dip net to remove dead fish and dead insects from the pond and then release 1/4-1/2 of the old water, after which you add new water of the same temperature and amount to the pond.

2. Complete water change

A complete water change is generally carried out together with emptying and redoing the tank, selecting young fish, or selecting adult fish, and is mostly used in cases such as relatively serious water quality damage, overly long moss in the pond, or overly dense fish stock.

1. If there is no idle pond, you can first place an oxygenation head in a basin or a net cage, then scoop all the koi carp into the water basin or put the net cage into the water of an adjacent pond for temporary holding, then scrub the moss off the tank walls, after which add new water at a suitable temperature to the tank, let it sit for a short while, and once the water temperatures are equal, scoop the fish back into the aquarium.

2. If there is still an idle pond and new water, scoop the koi carp into a basin or net cage, sort them according to size, put those that are to be separated into tanks into the tanks for keeping, and for those not to be separated, let them sit for a while until the water temperatures are the same and then move the koi carp into the new water. When changing the water, pay attention to the water temperature; around 9 a.m. on a clear morning is best. However, this water change method can only be used for adult fish or relatively large young fish; fry cannot use this method.

If conditions permit, before carrying out a complete water change, you can first fill a spare aquarium with aged water, then scoop the koi carp into the spare aquarium. Because the water temperature difference is relatively small, it is easier for the fish to adapt and can prevent the fish from being squeezed in the basin or net cage.

This water change method is generally carried out about once every 15 days in spring and autumn. In hot summer, when the pond water temperature reaches above 28°C, the pond water color easily becomes dark and the water quality easily becomes turbid, so a complete water change is generally needed about once every 5 days; in winter, when the water temperature is around 4°C, because the koi carp eat little and are not very active, the water quality is easy to maintain, so generally no complete water change is needed unless there are special circumstances.