Detailed Explanation of Key Points for High-Density Culture Techniques of Topmouth Gudgeon

AbstractSeed stock selection: fry should be selected with mature gonads, robust constitution, intact scales, and free of injuries, disease and parasites. Fry stocking: stock about 80,000-100,000 fry per mu. Fry management: feed once each morning and evening every day; you may feed self-prepared feed or mix it with live bait. Water quality management: ensure water circulation in the pond, and change more than 30% of the water every 5 days. Disease control: it is necessary to prevent cyclops, tadpoles and some bacterial diseases, etc.

I. Seed Stock Selection

1. When selecting seed stock, you should choose 2-year-old and older fry with a body length greater than 5 mm and a body weight greater than 3 g.

2. When selecting fry, check their gonad maturity, constitution, scales, presence of injuries or disease, and presence of parasites, etc.

3. Before stocking, they must also be disinfected with 35% salt water for about 5-10 minutes.

4. The density of fry is about 1,000-1,500 per mu.

II. Fry Stocking

1. The nursery pond area is about 700-1,300 sq m, the water depth is about 1.5 m, and the bottom needs silt of less than 10 cm.

2. About 75-100 kg of disinfectant per mu is needed to disinfect the nursery pond. After 7-10 days of disinfection, the nursery pond needs to be filled with water, and aquatic plants should also be planted at the bottom.

3. Stock about 80,000-100,000 fry per mu.

4. The nursery pond needs to be frequently changed with water, each change being about 30%.

5. The gonad development of the fry should also be checked frequently.

III. Fry Management

1. In order to promote gonad development, starting from late March, flush the water once every 5 days, with each flushing lasting 34 hours.

2. Feeding is mainly based on oil bran or self-made compound feed, fed 2 times a day, once in the morning and once in the evening; the feed fed can be self-prepared feed or mixed with live bait.

3. When feeding, the amount of feed should be about what the fish can finish within 2 hours, and the amount should be adjusted according to how the fish school feeds.

IV. Water Quality Management

1. In the early stage of the fry, the water level only needs to be low, about 50-80 cm.

2. As the fish grow and the water temperature rises, the water level should be slowly raised, about once a week, with each addition of about 20 cm of water.

3. It is best for the water in the pond to circulate continuously; try to change about 30% of the water every 5 days, and at the same time apply a microbial preparation once about every half a month to improve water quality.

V. Disease Control

1. It is necessary to adhere to the principle of “treat when diseased, prevent when healthy, combine treatment with prevention, with prevention first”.

2. In the early stage, it is necessary to prevent and control cyclops and tadpoles, etc.; once found, they can be killed with 0.3-0.5 mg per liter of crystallized trichlorfon, and at the same time the tadpoles in the water should be promptly removed.

3. For some bacterial diseases, sterilization and control can be carried out regularly with strong chlorine essence, chlorine dioxide and avermectin or deltamethrin, etc.