A Detailed Guide to Grass Carp Types and Scientific Farming Methods

Grass carp, one of the Four Major Chinese Carps of freshwater aquaculture in China. It is a fish endemic to the plains regions of eastern China, from Guangxi to Heilongjiang. So how many types of grass carp are there? How should they be farmed scientifically? Let us find out together below:

How many types of grass carp are there?

The grass carp belongs to the order Cypriniformes, family Cyprinidae, subfamily Leuciscinae, genus Ctenopharyngodon. The common names of the grass carp include: huan, huan fish, oil huan, grass huan, white huan, grass carp, grass root (Northeast China), houzi fish (southern Shandong), sea huan (southern China), hunzi, black bluefish and so on. It is lively in nature, swims swiftly, often forages in groups, and is a typical herbivorous fish. During the fry stage, the grass carp feeds on larvae, algae and so on; the grass carp also eats some animal food, such as earthworms and dragonflies.

The grass carp varieties mainly used in aquaculture in China are generally divided into three strains: the Yangtze River system, the Pearl River system and the Heilongjiang River system; no subspecies have been distinguished. New varieties include golden grass carp, crisp-fleshed huan and abalone-fleshed huan.

How should they be farmed scientifically?

1. Environment and pond selection

Grass carp are the most prone to illness. Farming pollution-free grass carp requires a dedicated aquaculture base of a certain scale, with no pollution sources around the base. The aquaculture base should have an ample water source, good water quality, smooth water intake and drainage, no connection between the ponds, convenient transport for the fish, abundant feed resources and good ecological and environmental conditions.

2. Fry selection

To raise grass carp well, healthy and lively high-quality fry must be selected. The parents of self-bred fry should come from qualified, state-recognized source farms; the fry should be produced through pollution-free cultivation, meet the relevant quality standards and possess the excellent traits of the variety. Where conditions permit, self-breeding is best; if fry are introduced from elsewhere, they may only be brought in after passing quarantine inspection.

3. Fry disinfection

Before the fry are put in, they must be disinfected. Options include chlorine dioxide at 20-40 mg/L for 5-10 minutes, salt at 1%-3% for 5-20 minutes, 8 mg/L for 15-30 minutes, and potassium permanganate at 10-20 mg/L for 15-30 minutes, among other medicated soaking disinfectants. Stock the fry at a ratio of 80:20, that is, 80% grass carp as the main species and 20% companion fish.

4. Scientific feeding

In natural waters, grass carp mainly feed on aquatic plants. In pollution-free pond farming, it is suitable to use scientifically formulated pellet feed to reduce water pollution from leftover bait and to fully improve feed utilization. Aquatic and terrestrial grasses fed as a supplement should be tender, fresh and palatable. Cake and meal types and other feeds must be free of mould, pollution and toxicity, and after being crushed, soaked or boiled, they should be made into feed that grass carp can easily take and digest. Feeding must adhere to the principles of feeding at fixed times, in fixed locations, of fixed quality and in fixed amounts, and a reasonable feeding amount must also be determined by observing the weather, water conditions and the fish's food intake.

5. Rational use of fishery drugs

Fishery drugs are substances used to prevent and treat diseases and pests of aquatic animals and plants. If used improperly, they can easily remain in fish bodies and make the fish substandard, so they must be used with caution. Fishery drugs generally include bactericides, insecticides, water quality improvers and so on. At present, some traditional fishery drugs have been banned, such as chloramphenicol, furazolidone, sodium pentachlorophenate, malachite green, sulfathiazole, tylosin and 32 other fishery drugs, which cannot be used in aquaculture; special attention should be paid when choosing fishery drugs.

Nutritional analysis

1. Grass carp is rich in unsaturated fatty acids, which are beneficial to blood circulation, making it a good food for people with cardiovascular disease;

2. Grass carp is rich in the element selenium; regular consumption has anti-aging and beauty benefits, and it also has a certain preventive and therapeutic effect on tumours;

3. For people who are thin and weak with a poor appetite, grass carp meat is tender without being greasy, and can stimulate the appetite and provide nourishment.