Thac Lac fish, also known as Nang Hai fish, is popularly bred in Vietnam, this is a commercial fish line, later crossed into many beautiful lines and is chosen by aquarists as ornamental fish. The model of strabismus fish farming is increasingly being expanded in many different directions. So Waterfall fish farming techniques What are the special features of the cage that are widely used? The following article will talk more about this topic. We invite you to take a moment to read the article.
Preparing the fish pond
Depending on the conditions of each farming household, the area of fish ponds is also slightly different. But normally, the pond for raising strabismus has an area from about 200m2 to 400m2. Pond banks must be firm, pond bottom must be flat, have active water supply and drainage, pond water has pH from 7-8 and dissolved oxygen greater than 3mg/liter, with water retention depth from 0.8-1, 2 m.
For ponds that have just been harvested and want to raise strabismus, it is necessary to improve the fish ponds in the following ways:
Drain the pond, dredge the bottom mud layer, leaving only a layer of mud no more than 30 cm thick.
Cut grass on the banks, pond roofs, plants in ponds, fill holes, leaks. Inspect and repair water supply and drainage drains.
Use insecticides to kill trash fish, evil fish and aquatic species harmful to fish, using 0.5-1 kg of fish medicine roots for 100 m3 of water.
Spread 8-10 kg of lime powder/100m2 on pond bottoms and banks to kill residual trash fish species and kill pathogens. In alum contaminated areas, the amount of lime is about 50% higher. After spreading lime, the lime must be mixed with the pond surface mud.
Apply manure to create the initial natural food for fish at a dosage of 10-20 kg per 100 m2 of pond. Or apply inorganic fertilizer (urea 0.5 kg, phosphorus 0.3 kg) or compound fertilizer (NPK) 2 kg for 100 m2 of ponds.
Then dry the bottom for 2-3 days. Ponds in alum contaminated areas should not be exposed to the bottom.
Filter the water into the pond until the water level reaches 0.5-0.6 m, then release the fingerlings. Then continue to put water into the pond until it reaches the specified level.
Select and release strabismus fish
You can refer to some criteria for choosing strabismus as follows:
- Choose healthy fingerlings
- Swimming briskly
- No scratches.
- uniform size no irregularity
It should be noted that it is advisable to choose to buy fingerlings at reputable aquatic breeding establishments and subsidiaries to avoid unsatisfactory harvest quality and fish production. In addition, if you have stocked polyculture with other freshwater fish species, you can refer to a few other species that can be cultured such as white catfish, giant catfish, coriander or galangal with a rate of no more than 50. % of total fish in the pond and also do not release fish species that compete for food with strabismus such as tilapia, pangasius.
Next is how to stock fish fry. Should choose to drop fish into the pond in the early morning or cool afternoon. Before releasing fish into the pond, it is necessary to soak the bag of fingerlings in water for 15-20 minutes to balance the temperature inside and outside the fish bag, then open the mouth of the bag to release the fish out of the pond.
Feed the fish
When the new fingerlings are released into the pond, we both use natural food in the pond and feed other foods such as processed mixed feed and live food (some other livestock by-products).
About the first 2 weeks, people should feed the fish at the following ratio: 50g of bran mixed with 50g of cooked fish meal, mixed well for about 1,000 fingerlings.
The following weeks: Feed at the rate of 50% processed food (bran + fish meal) and 50% fresh food such as trash fish, fresh fish chips, snails, shrimp… Can be fed with bran, broken fish , mix light fish meal at the ratio of 30% fish meal + 70% bran plate. It is recommended to feed fish with the floor to monitor and adjust the amount of aquatic food accordingly.
In addition, it is necessary to feed the fish with industrial feed, which is small and medium-sized, with a protein content of 25-30%, the ratio of industrial pellets is about 30%.
Note: It is recommended to feed fish twice a day, because fish are active at night, feed in the morning equal to 1/3 of the daily diet, in the afternoon, 2/3 of the weight of the diet. during the day.
The ration of processed feed is 5-7% of fish weight/day.
The diet of industrial pellets is 1.5-2 % fish weight/day.
Regularly supplement vitamin C and digestive enzymes for fish. Occasionally mix garlic into the food at a dosage of 50-100 gr/10 kg of food to keep fish healthy and limit some common diseases in freshwater fish.
Care and management of fish ponds
Daily pay attention to inspect the banks of ponds and culverts, promptly detect and repair banks, nets, fill holes and prevent rainwater overflowing the banks. Change 30-50% of the water in the pond every week. When the pond water is too dark green, dark brown or has a bad smell, the old water must be drained and new clean water supplied to the pond.
Despite regular care and management of ponds, fish are still susceptible to some diseases like other freshwater fish. The strabismus can be infected with parasites such as the wheelworm (Tricho dina), the melon worm (Ichthiophthyrius), parasitic crustaceans such as the anchor worm (Lernea) and the fish louse (Argulus), the simple fluke. host 16 hooks (Dactylogyrus), 18 hook flukes (Gyrodactylus) or roundworm infections (Philometra).
When the fish is sick, it often swims scatteredly and swims slowly to the surface, which is a sign that the fish is sick. People should pay attention to some of the symptoms of fish to early detect the disease as well as treat according to the suggestions below.
The skin of the fish appears grayish-white with small soft myceliums, strong growth of mycelium and clumps like cotton that can be seen with the naked eye.
Treatment: Bathe fish in 2-3% salt water for 5-10 minutes.
The skin of the fish is gray, the body of the fish has a lot of slimy, slightly milky color.
Treatment: Bathe fish in 2-3% salt water for 5-15 minutes or CuSO4 concentration of 2-5ppm for 5-15 minutes. or spray directly CuSO4 concentration 0.5- 0.7ppm into the pond.
The body of the fish has many worms clinging to small, opaque white seeds that can be seen with the naked eye, the fish floats on the surface of the water.
Treatment: CuSO4 sprayed into the pond at the recommended dose for treatment.
After a period of 10-12 months, the fish can reach a size of 700-800g. The best way to harvest strabismus is to drain the water, pull the net to collect some, then drain the water to catch the fish thoroughly. It is possible to harvest at the same time when the price is high or to trim the large fish and re-raise the small fish that have not reached the size.
We hope that with the information we share, it will be a way for farmers to implement the strabismus farming model for themselves. Wish the farmers success and great profits.