What is the suitable temperature for crucian carp farming?

SummaryCrucian carp is highly adaptable, and its temperature requirements are not very strict either. From a high temperature of 32°C down to a low temperature of 0°C, crucian carp can grow normally. Whether in deep water or shallow water, whether in flowing water or still water, crucian carp can grow and reproduce. Even in Dalai Lake, where both pH and salinity are very high, they can still grow normally, so farming crucian carp is still quite easy.

Crucian carp has very strong adaptability. Whether the water is deep or shallow, still or flowing, relatively warm or relatively cold, it can survive. Even in strongly alkaline, highly saline waters such as Dalai Lake, where the pH is as high as 9 and the salinity is as high as 4.5%, it can still grow and reproduce normally.

1. Farming crucian carp in rice paddies

As long as the soil is fertile, irrigation is convenient, and the rice paddy has good water retention and fertilizer retention, crucian carp can be farmed there. Crucian carp farming generally uses continuous farming with double-cropping rice, because the time for single-cropping rice is relatively short and it is difficult to reach the size of adult fish. Before releasing the fry, field ridges, fish pits and fish ditches should be dug and built in the rice paddy according to the paddy area, water source, and inlet and outlet conditions.

The piled field ridges are required to be sturdy and not leak water; the area of the fish pit varies by region, and should be controlled at a minimum of 3-5 sq m/mu. Where the area is large, it can be about 20-30 sq m/mu. Generally, the best is to control the fish pit area at about 5%, and the water depth in the pit at about 80cm; the number of fish ditches is determined by the shape and size of the rice paddy. Generally, forms such as the “one” shape, “ten” shape, “shi” shape, “mouth” shape and “thirty” shape can be used.

When farming crucian carp in rice paddies, they can be farmed alone or mixed with other fish. Generally, fry with a size of 5-6.5cm are best. Release is best carried out one week after transplanting the early rice, and the stocking density should be controlled at about 250-500 fish/mu. If no bait is fed into the rice paddy, then generally after autumn more than 20kg of crucian carp with an average size of about 100g can be harvested. If some concentrated feed is fed during the farming period, then generally about 35kg of crucian carp can be harvested.

The daily management of farming crucian carp in rice paddies is the same as farming other fish. Organic fertilizer should be applied regularly to the rice paddy to cultivate the water quality in the field and promote the growth of crucian carp. Anti-escape facilities should be set up around the rice paddy to prevent crucian carp from escaping, and disease and predators should be prevented.

2. Farming crucian carp in small reservoirs and lakes

Generally, small lakes or reservoirs with fertile water quality and rich natural bait available for crucian carp to feed on are selected for farming. Using lakes and reservoirs with intensive or semi-intensive farming through feeding and fertilizing to farm crucian carp will achieve the best results. Choosing lakes or reservoirs where the lake or reservoir has been dried and fish have been caught within 1-3 years to farm crucian carp will generally give very good crucian carp yields.

The water surface of lakes and reservoirs is relatively large, and there are relatively more predator fish in the water. When releasing, it is best to choose larger-sized fry, and the stocking density can be controlled at about 20-50 fish/mu to improve the survival rate of crucian carp.

Fry can be released in both spring and winter. In high-yield lakes and reservoirs where water is released and fish are caught every year, the number of crucian carp released can be appropriately increased. During the farming process, management can follow the techniques for farming crucian carp in ponds.

Generally, crucian carp farmed in lakes with sufficient natural bait and fertile water quality grow faster, and they will even exceed their growth rate in ponds. Generally, the fry released in the same year can reach a size of more than 250g. In lakes and reservoirs where the lake or reservoir has been dried within 2-3 years, crucian carp with a size of more than 500g also account for a relatively large proportion.