Surely everyone saw them at grocery stores on the fish counters of marble catfish. And many people like this type of fish, because its meat is quite juicy, soft and tasty. But not everyone knows that this fish can be grown quite easily on its own or on a small fish farm. In the article, we will consider the rules for breeding and rearing fish in the farm, but you can grow catfish in the same way for personal consumption.
Catfish
In general, βmarble catfishβ is not quite the correct name for this fish. In fact, its name is African Clarium catfish (lat. Clarias gariepinus). These fish come from Africa. Even in the Sahara, you can catch Nile Clarias. It looks like a completely ordinary catfish: its long body in brown spots has a light abdomen. A distinctive feature of all catfish is a long mustache. Clarius mustache already has 4 pairs. This species of fish is able to process oxygen from the air using the suprajugal respiratory organ. For this purpose, catfish emerges to the surface and is saturated with air. It was this feature that made Clarius so convenient to breed. There is no need to provide it with fresh water. Moreover, about 300 kilograms of live fish can be planted per cubic meter of water. Of course, this is only possible with regular removal of feces.
To maintain a large number of fish, you must either purchase special pools or have access to fairly large reservoirs. One of the features of the method is the possibility of further use of warm water from incubators, which leads to better results.
Manufacturers
For the most part, the parent herd is fish that grow faster than others. African catfish can participate in breeding by 1.5 - 2 years. The female reaches puberty by 6 months, but the best results are obtained at the age of 2 years.
Usually, during breeding, the parent herd is kept in separate tanks, in which the water is warmed up to 23-25 degrees Celsius. Feed manufacturers must be carefully balanced. The protein content in such feed should be at least 38%. Producers must consume at least 1.5% of their weight per day.
The optimal number of producers in one fish receiver is 100 individuals.
Reproduction under control
Most often, to obtain high-quality sex products, manufacturers are stimulated with injections of hormones. Before the introduction of the hormone, it is necessary to distribute the females to various aquariums or pools.
2-3 days before the spawning procedure, you need to put the fish on a hungry diet. With a single injection, the pituitary gland is used, at a rate of 4.5 mg per kilogram of live weight of the fish.
African catfish, which it was decided to breed by injection, responds well to Ovopel. It is administered once, using 1 pellet per kilogram of fish. This medication is used as a physiological mixture. The males are kept in one pond until spawning.
Spawning
For successful maturation of eggs, it is necessary to keep females in water with a temperature of about 26 degrees until spawning. Complete ovulation occurs 12 hours after the injection of the pituitary gland.
African catfish is a rather nervous fish, therefore, to obtain the eggs of females it is necessary to euthanize. This is done by introducing an anesthetic drug. The most commonly used is Propiscin.
Caviar is obtained from each female separately. In this case, it is considered permissible if the mass of eggs is at least 20% of the weight of a particular individual. After the procedure, the female is placed in KMnO4 for a period of about an hour. The drug must be diluted at the rate of 0.5 g per 100 liters of water.
Milk for the most part is taken from gonads of already caught males. Sperm efficiency lasts up to 24 hours at a single temperature - 4 degrees.
Fertilization
The resulting caviar is divided into three parts. Caviar of different females is better not to mix. Each serving should weigh approximately 300 grams. Then take 3 ml of milk. Efficiency will be higher if the milk is from different males - this stimulates the fertilization process. Thus, it is better to take 1 ml from 3 males. Dip the milk and caviar in water and mix well for about five minutes.
Degumming
After fertilization, the caviar should be washed well. To do this, use a solution of tannin. It takes about 10 grams per 10 liters of water. In order to completely de-gum the caviar, it is necessary to thoroughly rinse it in solution for no more than 30 seconds.
Incubation
After the caviar is degummed, its incubation begins in the trays on the frame or in special devices. The incubation frames should be covered with a mesh with a mesh of about 0.5 mm. Caviar is distributed on the grid with a layer of 1 egg. At a water temperature of no higher than 27 degrees, larvae appear. From the moment of fertilization until the appearance of the larva, about 25 hours pass. Water in the trays is consumed at a speed of 10 liters per minute.
Larvae aging
The larvae must be kept in trays or small pools until the yolk sacs are resorbed. You can place the larva in the pool for the first two days, then move it to the trays.
African Clari catfish larva should be kept in the dark. Three days after the final resorption of the yolk sac, you must remove the mold-covered film from the bottom of the tray. If the larvae become active, then the yolk sac is finally dissolved.
Stages of growing larvae
The first stage lasts about 3 weeks. Its end occurs when the African catfish begins to breathe oxygen from the atmosphere.
Landing of the larva during this period is about 100 per liter of water. Water should be constantly saturated with oxygen, its exchange should be established in the pool. Feed the larvae with decapsulated brine shrimp or tubule. After a week, starter feed is introduced into the diet. Lighting should be dim or twilight.
Larvae are characterized by cannibalism, therefore, by the end of the first stage, the content of fry will naturally decrease to 25-50 pieces per liter of water. You need to sort future fish in the third week. Such an intervention can anger the larvae, so sorting should be done very carefully. After that, the fish is left in the antibiotic solution for an hour.
The second stage lasts about 5 weeks. Usually this cycle begins with filling the pool with well-sorted larvae. Their number should be approx. 300-500 mg. Larvae should be sorted into 2 parts by size.
Most often, African male catfish sits down when taking into account the specific gravity of fish and the volume of the basin. The daily ration, divided into 3 meals, should be approximately 5% of the weight of the fish.
The next stage is about two months. Fish in this period should weigh 130-200 g. The growth rate of the fry depends on the density of planting. For a pool of 5 thousand liters, the planting density is 2.5 pieces per liter. Water temperature within 27 degrees.
During the third stage, the main feed for African catfish is floating. The feeding process is automated or manual. Water must be replaced after 2 hours.
Growing
Growing African catfish to a marketable appearance takes approximately 50 days from the completion of the third stage of larval cultivation. The average weight of the fish at the end of the whole process can be up to 2 kilograms. During this stage, African catfish is located in pools with a capacity of about 10 cubic centimeters. Two liters of water can plant no more than 3 fish. This method gives about 400 kilograms of live fish for every cube of water.
Most often, fish are fed at this stage with floating feed. The volume of food is about 3% of the weight of the fish. It must be fed about 5 times a day.
Excellent results can be obtained using Reflex feeders. One feeder of this type is used per 10 squares of the pool area.
Manual feeding ensures a more even distribution of food. This leads to differentiation of the mass of fish. African catfish, breeding which takes place in a controlled way, shows significant gains in a fairly short period of time.
After all stages are completed, the fish are sorted. The individuals who showed the best rates of weight gain and growth are left for further reproduction, the rest of the fish is sent for sale. Pools and trays after growing fish are washed and cleaned until the next generation. Before new use, they are treated with an antiseptic solution.
Given the rather high average water temperature , it is possible to breed African catfish only in the south of Russia. Currently, catfish are being raised in the Temryuk district of the Krasnodar Territory.