Detailed Explanation of Key Points on Pufferfish Pond Cultivation Techniques

I. Small-Size Fingerling Cultivation

(I) Pond Selection Ponds require an abundant water source, unpolluted water quality, and small annual water temperature fluctuations. If brackish or freshwater aquaculture is used, ponds should be built in locations where water can be pumped conveniently, with short routes and low pumping heads. The pond bottom should be basically non-leaking and non-seeping, and it should be relatively easy to build dikes and gates. In addition, transportation and power supply should be convenient, there should be no tall buildings around the pond, and it should not be easily impacted by storms or floods.

(II) Pond Cleaning and Disinfection In winter or during the slack farming season, drain the water from the pond, dig out the mud at the bottom, and then expose it to sunlight naturally. Before stocking fingerlings, quicklime, bleaching powder, etc. should be used to clear the pond and disinfect it. The dosage of quicklime is 100-150 kg per mu, and the dosage of bleaching powder is 30-40 ppm. After one week, fill with water and release the fish, and apply sufficient base fertilizer to promote the reproduction and growth of plankton.

(III) Fingerling Stocking After fingerlings are cultivated indoors to 1.2-1.5 cm, stock 10,000-20,000 per mu. For shorter transport distances, plastic buckets with water can be used; for longer transport distances, plastic bags with oxygen should be used, with 800-1,000 fish per bag. Survival rate can be guaranteed within 7-8 hours of transport. The transport water should preferably be 3-5 ppm salt water. When stocking, the temperature should be above 18 degrees C, and care should be taken that the temperature difference inside and outside the bag is not too large.

(IV) Feeding and Water Quality Control Before the fingerlings reach a total length of 3 cm, feed 1 kg of soybean milk per mu of pond each day to propagate plankton and provide sufficient food for the fingerlings. At the same time, pay attention to transparency, generally around 30 cm; the water color should be mung bean green, with abundant plankton in the water, but it should not form clumps or groups, and should not gather and rotate in the water. If there is too much food organisms, new water should be injected to reduce the biological density and keep the water quality fresh. By effectively regulating dissolved oxygen and water quality, most fingerlings can reach about 3 cm in size after 20 days in the pond. At this time, while feeding soybean milk to control food organisms, use eel feed to make soft pellets the size of soybeans and place one pellet every 1 meter on the bank to acclimate the fingerlings to the habit of eating eel feed. At this point, they should be divided and thinned for large-size fingerling cultivation.

II. Large-Size Fingerling Cultivation

(I) Fingerling Transport and Stocking To ensure fingerling quality, the dark-banded pufferfish should be authentic fingerlings. Select individuals with strong physique, no disease or injury, uniform size, and strong upstream-swimming ability as stocking subjects. Transport generally uses plastic bags with oxygen, with 100-150 fry per bag for 3-4 cm fry, and they can be transported for 5-8 hours with a survival rate above 95%. Before stocking, it is best to disinfect the fry with 5 ppm bleaching powder or 1 ppm malachite green for 10 minutes. When stocking, care should be taken that the temperature difference is not too large. Dark-banded pufferfish should be stocked at low density. For 3-5 cm fingerlings, the pond stocking density is 2,000-3,000 fish per mu. For ponds with abundant water sources, good water quality, and large water exchange capacity, the stocking density can be appropriately increased to 3,500-4,000 fish per mu. As the fish grow, gradually catch the large ones and leave the small ones, and divide and thin the cultivation.

(II) Acclimation After domestication, dark-banded pufferfish can be fed minced miscellaneous fish, shrimp, snail meat, mussel meat, etc. Within one week of stocking the fry, use fresh and palatable fish meat, shrimp meat, shellfish meat, etc. as the initial feed for acclimation, so that they gradually adapt to the culture environment and feed composition. After the pufferfish become accustomed to eating, gradually mix artificial feed into the bait and gradually increase the amount of artificial feed until they completely eat artificial feed. Ensuring the freshness of the bait during the acclimation period is the key to successful acclimation.

(III) Feeding The feed is mainly eel feed. The daily feeding amount accounts for about 3%-7% of the fish body weight. When feeding, it is necessary to feed at a fixed location (fixed feeding position), fixed amount (feed more when eating more, feed less when eating less, based on the principle of fish eating their fill), fixed speed (feeding speed follows the principle of slow-fast-slow), and fixed quality (the bait is palatable, fresh, and clean). Generally, feed twice a day. It is best to set up feeding platforms in the pond so that feeding conditions can be checked in time. If there is still leftover bait on the feeding platform two hours after feeding, the feeding amount should be reduced. The feeding platforms should be frequently cleaned and sun-dried to prevent bacteria from breeding.

(IV) Water Quality Regulation Pufferfish prefer an environment with fresh water quality. Pond aquaculture should add new water irregularly according to water color, water quality, transparency, dissolved oxygen, and the activity of fish and shrimp. A major water change should be done once a month to improve water quality. Since the suitable growth temperature range for pufferfish is 9-32 degrees C, when the pond water temperature exceeds 32 degrees C in summer, low-temperature deep well water or river water needs to be injected to regulate the pond water temperature. In winter, when the pond water temperature is below 9 degrees C, they need to enter a greenhouse to overwinter. In addition, pufferfish have relatively high requirements for dissolved oxygen. When dissolved oxygen in the water is below 1.5 g per liter, they begin to surface for air; when it is below 1.3 mg per liter, they begin to die. The suitable dissolved oxygen level should be maintained above 3 mg per liter. When dissolved oxygen is insufficient, an aerator or air pump should be used to increase oxygen.

(V) Separate Cultivation by Different Sizes Pufferfish of different sizes differ greatly in food-grabbing ability. When competing for food, larger individuals often attack smaller individuals, seriously affecting the feeding and growth of the smaller individuals. Therefore, individuals of different sizes should be raised separately. Separate cultivation is generally carried out once every 30-45 days. Ensuring sufficient feeding, timely separation, and appropriate thinning can effectively prevent mutual killing among fish and improve the survival rate of cultivation.

(VI) Daily Management Persist in patrolling the pond every day, observe the activities of the pufferfish, feeding, water color, and water quality conditions, and inspect the cultivation facilities. Measure the physical and chemical factors of the water body regularly every day, such as water temperature, pH value, dissolved oxygen, ammonia nitrogen, COD, PO4-P, transparency, etc., and keep daily records to help summarize experience and lessons and guide future production. Measure the fish growth condition every 10-15 days and keep records as a reference basis for feeding. Through 4.5 months of careful rearing, the size of the fingerlings in the same year can reach 100-150 g, and the survival rate can remain stable at 85%-95%.