African sharptooth catfish breeding and rearing in fish farming

 

The African sharptooth catfish, or marbled sharptooth catfish, or Nile sharptooth (lat. claria gariepinus) is found throughout Africa, including the waters of the Sahara, in the Jordan River basin, in South and Southeast Asia. In recent decades, the African sharptooth catfish has been acclimatized in Russia and the CIS countries, where it occupies its niche in pond fish farming, when sharptooth catfish are grown in aquaponic modules, RAS and cages, where it has many advantages over other traditional fish species. The features of growing and breeding sharptooth catfish in aquaculture will be discussed in this article.

Content

• What does a sharptooth catfish look like?
• Conditions for African catfish when breeding at home
• Clarium catfish breeding as a business
• Diet of sharptooth catfish
• Development of sharptooth catfish in Russia
• Controlled breeding of African catfish
• Obtaining caviar - spawning of African sharptooth catfish
• Fertilization process of African sharptooth catfish eggs
• De-gluing of African sharptooth catfish eggs
• African sharptooth catfish egg incubation process
• The process of keeping African sharptooth catfish larvae until the yolk sac is reabsorbed
• Effect of African Clarid Catfish Stocking Density on Growth Rate
• Cultivation of commercial fish African sharptooth catfish
• Food for sharptooth catfish and feeding of African sharptooth catfish
• Food for sharptooth catfish
• Growing African catfish at home
• African catfish roe

 

 

What does a sharptooth catfish look like?

 

What kind of fish is Clarid catfish? In appearance, the sharptooth catfish has a long body that is slightly laterally compressed, sandy yellow to gray in color, covered with brown, olive, greenish-brown spots, and has a light belly. The catfish has a large, slightly compressed head, small eyes with a narrow and angular process of the occipital bone. Clarius has a large conical mouth. A distinctive feature for all catfish is their long mustache. Clarius has 4 pairs of whiskers above his mouth. The African sharptooth catfish has long dorsal and anal fins. The caudal fin is rounded. 

The African sharptooth catfish has developed a special organ for breathing atmospheric oxygen. A tree-like branched epibranchial organ extends from the gill cavity, the walls of which are penetrated by many blood vessels and have a very large surface. In other words, this is a real lung that replaces the gills while the African catfish is out of water. 

Special studies have shown that the epibranchial organ of Sharptooth contains only air and is most effective at an air humidity of 81%. Complete shutdown of breathing through the gills leads to death after 14–47 hours.

 

 

Conditions for African catfish when breeding at home

 

Sharptooth catfish feel best when the concentration of oxygen dissolved in water exceeds 4.3 mg/l and access to the water surface is not difficult. The optimal habitat for the African catfish is water with a pH of 6.5–8.0 and a temperature of 25–30 °C, but it also tolerates temperatures of 12–18 °C, is resistant to temperature changes up to 35 °C, and tolerates salt levels in water up to 10 ppm With a high growth rate, the African catfish does not require perfectly clean water; it does not tolerate high levels of ammonia and nitrates in the water.

Stocking density of Clarii catfish

 

African catfish are able to withstand high fish densities without reducing their growth rate. It is believed that 300 kg of clarius catfish live freely on a cubic meter of water, and sometimes it reaches up to half a ton. The growth rate of African catfish is very high. 

However, if the African catfish does not like the conditions in the reservoir, then in rainy weather it will crawl to another reservoir. 

 

Diet of sharptooth catfish

 

What to feed Clarid catfish? The clarium catfish is quite omnivorous: it can feed on water beetles, larvae, mollusks, fish, plant foods and even organic waste, but in natural conditions it is mainly a predator. Due to the fact that catfish have a large mouth, it often happens that large individuals swallow smaller ones, therefore, when breeding sharptooth catfish at home, it is necessary to take into account their tendency to cannibalism and periodically sort the fish by size. It is believed that the sharptooth catfish can lead to an ecological imbalance in ponds, due to the maximum extermination of the local ichthyofauna, where only it can take root. 

Thus, it is possible to grow African sharptooth catfish in low-water regions of Kazakhstan, Uzbekistan and other Central Asian countries, in the southern and central regions of Russia.

Development of sharptooth catfish in Russia 

This type of fish has long taken root in the territory of our country (Kursk and Moscow regions) and has reached the Krasnodar Territory. As it turned out, this type of catfish is not demanding in cultivation and may well become one of the popular areas of agricultural activity in the Krasnodar Territory.

The controlled and controlled process of reproduction of African catfish has been widely known since the last century. This method is especially beneficial and effective in fish production conditions, not only in large fish farms, but also in specialized farms, for example, in fish hatcheries that produce planting material. 

In the process of breeding African catfish, special equipment is required in the form of special pools filled with purified water from wells or water from open reservoirs. One of the main features of using this method is the ability to use warm water from the incubator, which further contributes to good results when growing African catfish. Breeder stock As a rule, the parent stock is formed from fish with high growth rates. Usually gender Females reach maturity after approximately 6 months. The best results during reproduction are achieved by females aged about 2 years. As a rule, male African catfish who have reached the age of 1.5 - 2 years have developed and full-fledged gonads. Moreover, males after 1.5 years of age have good, developed gonads. As a rule, during the breeding process, African catfish producers must be kept in separate pools in which the water temperature is 23°C - 25°C. The composition of the feed for producers, it is desirable that it be strictly balanced with the obligatory presence of a protein percentage of about 35 - 38%. The mandatory daily diet for African catfish producers should be about 1.5% of biomass. The recommended number of producers in a fish hatchery is at least 100.

 

 

Controlled breeding of African catfish

 

As a rule, in order to effectively obtain healthy, sexual products, stimulation is carried out using hormonal injections. Moreover, before the injection, it is recommended to distribute the females into separate pools or aquariums. In addition, it is also necessary not to feed the fish approximately 2 days before spawning. For a single injection, it is necessary to use the pituitary gland in an amount of about 4.5 mg/kg of the female’s weight. In addition, for a single injection, it is recommended to use the drug “Ovopel” in the amount of 1 granule/kg of weight. This drug is usually used as a liquid physiological mixture in a volume of 0.3 ml/kg of body weight. Usually, until the moment of spawning, all males, as a rule, are in the same pool.

Obtaining caviar - spawning of African sharptooth catfish 

 

Clarium catfish spawning. When breeding African catfish at the time of spawning, it is necessary to maintain an optimal temperature in the pool of about 26°C for the successful maturation of females. In addition, it is generally accepted that the required optimal temperature for the effective process of complete ovulation of eggs should be 25°C - 26°C. Complete ovulation occurs approximately 12 hours after the pituitary gland injection. Before obtaining eggs, the females must be euthanized. The process of euthanasia of females is carried out by administering a drug that has the ability to cause anesthesia; the most recommended drug is “Propiscin”. As a rule, eggs are obtained separately from each female. In this case, the permissible weight of eggs from each female is about 20% of the female’s weight. As a rule, milt is obtained from the gonads of captured males. In this case, male sperm should be effective for 24 hours at a constant temperature of 4°C. After taking the eggs, the females must be placed for 1 hour in a KMnO4 solution diluted in the amount of 0.5 g / 100 l of water.

Fertilization process of African sharptooth catfish eggs

 

As a rule, caviar taken from each female individually must be divided into several portions weighing about 300 grams. And also, you need to add no more than 3 ml. milk taken from 3 different males to activate and stimulate the fertilization process, add water and mix thoroughly for about 5 minutes.

De-gluing of African sharptooth catfish eggs

 

After the fertilization process, it is necessary to thoroughly wash the eggs. To wash caviar, a tannin solution is usually used in a ratio of 7–10 g. for 10 l. water. To completely destick eggs, washing in the solution is carried out for no more than 30 seconds.

African sharptooth catfish egg incubation process

After the degluing process, the eggs undergo an incubation process in special devices or in trays on special frames, which are lined with a mesh with mesh sizes of 0.5 mm. Caviar is usually placed in a thin layer. In about 25

hours at a temperature of no more than 27°C, larvae appear. The water flow rate in the trays is approximately 5–10 l/minute.

The process of keeping African sharptooth catfish larvae until the yolk sac is reabsorbed

The process of keeping the larvae until the yolk sac is completely reabsorbed must be carried out in round pools or in special trays. Two days after being in the pool, the larvae are usually transferred to trays. It is necessary to keep the larva in the dark for the entire period of time. About three days after the process of resorption of the yolk sac is completed, it is necessary to collect the moldy film from the bottom. Active movement of the larvae is one of the indicators that the yolk sac has completely dissolved.

African sharptooth catfish larvae are reared in stages.

The first stage of raising larvae usually lasts for 3 weeks, and continues until the moment when the fish switch to breathing atmospheric oxygen. As a rule, the planting density during this period ranges from 50 to 150 pieces/liter. In this case, the level of oxygen saturation of the water should be about 50 - 70%. It is necessary that the water in the pool is exchanged about 1-2 times/hour. In addition, the required volume of the pool or tray should be no more than 1000 l, and the depth is 50 - 60 cm. Twilight is one of the most important lighting conditions.

As a rule, the diet of larvae in the first 2-4 days of life includes live, decapsulated brine shrimp or tubifex (Tubifex). Then, after 4–5 days, the larvae’s diet gradually changes. During this period, the larval feeding diet includes dry starter feed, which contains 55% protein and about 14% fat. Typically, two weeks after the start of larval rearing, the fish stocking density ranges from 20 to 50 fish/l. At the same time, the level of the daily feed ration is about 15% of biomass. Feeding of larvae is done manually or automatically.

A distinctive feature of the African catfish is cannibalism, which is quite common. Cannibalism appears among the larvae several days after the start of development. Sorting of larvae must be carried out in the third week of growing larvae, the average weight of which is about 300 - 500 mg. The sorting process negatively affects the character of the larvae, so sorting must be done carefully. After the sorting process is completed, the fish are usually immersed for 1 hour in a solution with the antibiotic drug Oxytetracycline, diluted in a ratio of 50g/1000l. At the same time, it is necessary to maintain constant cleanliness in the pool.

The second stage of raising the fry lasts approximately 5 weeks. Moreover, the duration of the cycle directly depends on the organization of production. As a rule, the second stage of fry rearing usually begins with the tanks being filled with sorted grown larvae, the amount of which is approximately 300 - 500 mg. At the same time, the larvae are sorted by size into at least two groups.

Typically, the fish stocking density is planned depending on the specific gravity of the young fish, also on the volume of the pool, the time of rearing the young fish without the sorting process and the production cycle.

When feeding fry, it is customary that under optimal conditions the composition of the feed ration should be about 5% of the fish biomass. In this case, the daily food ration is usually divided into three to four servings.

Effect of African Clarid Catfish Stocking Density on Growth Rate

Typically, in the third stage of growing African catfish, which lasts approximately 60 days, the weight of the fish is about 130 - 200 grams. During this period, it is necessary that the pool capacity is about 5000 liters. And at the same time, the planting density was approximately 2.5 pieces/l. It is important that the water temperature in the pool is an average of 27°C. As a rule, in the third stage of fish farming, its feeding consists of floating feed with a volume of about 5% and is carried out manually or automatically. In this case, the water in the pool is exchanged every 2 hours.

Cultivation of commercial fish African sharptooth catfish

 

Typically, the final stage of fish farming lasts on average from 30 to 50 days. Moreover, the average weight of fish is 800 – 1200 grams. Fish farming at this stage is usually carried out in tanks with a capacity of approximately 10 m3. Moreover, the stocking density is 0.8 – 1.5 fish/l. With this result, you get about 400 - 500 kg of fish from 1 m3. The temperature level during fish growing at the final stage is 25 – 27°C. As a rule, the fish feeding diet consists of floating food in a volume of approximately 3% of the fish biomass. Feeding occurs every 5 hours.

Usually, good results are obtained by constantly using one Reflex type feeder, which is used for 10 - 12 m2 of pool area. The process of manual feeding, as a rule, results in a more uniform distribution of feed and a more differentiated distribution of fish by weight.

Food for sharptooth catfish and feeding of African sharptooth catfish

 

What to feed Clarid catfish? Feeding sharptooth catfish depends on the age of the fish and physiological state. 

What to feed African catfish fry? When African catfish are raised in ponds, the fingerlings feed on all kinds of aquatic invertebrates. To improve the nutritional base, ponds must have underwater areas abundantly overgrown with soft plant matter - this is necessary for the development of herbivorous chironomids, which constitute the main diet of African catfish fry.

When kept in an artificial reservoir at different stages of growing African catfish, the feed may vary greatly. The larvae, several days old, feed on various large zooplankton; by two weeks they need to be fed small chironomids (mosquito larvae). Artemia nauplii (small crustaceans), as well as starter feed in the form of a paste, are well suited for feeding African catfish larvae. African catfish larvae should receive food 10-12 times per day.

What feed is needed for African catfish? When the larvae reach about 100 mg in weight, the amount of live zooplankton in the diet can be reduced to 20-25%. The main feed from this moment and in the next 40-50 days becomes starter feed with adding ground spleen.

The next stage begins from the moment the larvae reach a weight of 1 gram, and until the weight increases to 5 grams. For these purposes, mixed feed intended for trout fingerlings is suitable, with the addition of ground spleen and premixes (the ratio of dry and paste feed should be 1 to 1). The number of feedings per day is 6-10 times, the dosage of feed is 10% of the live weight of the fish (per day). The next stage starts when the larva gains a weight of 5 grams, and ends when it reaches 15-20 grams (usually this takes from one to one and a half months). The diet used is the same as for feeding fish at the previous stage, but the frequency of feeding is reduced to 3-4 times a day, and the volume of feed is reduced to 6% of the live weight of the fish per day.

In winter, adult fish (hibernating) do not need food, but fingerlings must be fed. The amount of feed depends on the water temperature - the higher it is, the more food is required for sharptooth catfish:

• +7-8°С - 0.5-1% of live weight.
• +9-11°С - 1-2% of live weight.
• +12-13°С - 3% of live weight.

The composition of the feed can be the same as that used in the summer. As an alternative, it is allowed to use frozen and fresh fish, minced with the addition of 1% premix for trout.

When kept in cages in autumn-winter, the weight of fingerlings increases by an average of 15-20%.

Adult catfish, starting from two years old, are fed 2 times a day. The standard diet of African catfish is trout feed and paste-like admixtures. The daily dose should not be less than 4-5% of the live weight of the fish.

Before spawning, it is recommended to feed sexually mature female African catfish with the following composition: trout feed (in granules), minced fish or a mixture of minced meat with spleen (1 to 4) 40-50% plus trout premix - 1%. When keeping African catfish in a pond, you can feed the producers with live fish (about 30% of the diet). African catfish should be fed twice a day - in the morning and throughout the day.

DIY food for sharptooth catfish

Making food for clarium catfish with your own hands is not difficult. The main type of food for clarium catfish is any weed fish, which we have in abundance in the Krasnodar region. Catfish readily feed on sprat, anchovy, ruff and gerbil.

The feeding coefficient of the sharptooth catfish is high; in order to increase 1 kg of mass, the sharptooth catfish needs to be fed 3 kg of fish.

Feeding technology for sharptooth catfish. It’s better, of course, to feed small fish so as not to waste time on grinding. But at the first stage of rearing, this process is inevitable, since the catfish is not yet able to swallow the food whole. But after 10 days, feed fish need not be crushed. Trash fish can be fed directly frozen, in small slabs or in the form of minced fish balls. The daily food intake for catfish is 3% of its total weight in the reservoir. This norm is divided into 3 feedings (morning, lunch, evening). Clarium food is distributed evenly over the entire pond area. You need to feed every day; interruptions in feeding can lead to cannibalism and, accordingly, losses. 

Food for clarium catfish grown in cages can be prepared from a mixture of crushed trash fish, such as crucian carp and grain waste, with three parts of grain waste taken for one part of trash fish. 

Clarid catfish can also be fed with factory-produced granulated feed, but these feeds are much more expensive. Slaughterhouse waste and by-products can also be used as food for sharptooth catfish, the main thing is that the mass fraction of fat in the feed does not exceed 15%. For example, on fish farms in the Moscow and Kursk regions, bird crops are used as the main catfish feed, which remain after the birds are slaughtered in poultry farms. They are crushed together with the contents and fed in this form. Clarid catfish only need one type of food and do not need additional feed additives. In this regard, the meat of clarium catfish is healthy and environmentally friendly.

In terms of biological value, fish proteins are not lower than those of farm animal meat, but they are easier to digest and assimilate by the human body. Clarius catfish meat has excellent taste, different from ordinary catfish, is pink in color, has no foreign odors and can be used in the production of semi-finished products and even sausages. Sharptooths is suitable for boiling and frying; it contains few small bones. Clarius catfish eggs are also edible.

 

 

Growing African catfish at home

 

Growing clarium catfish at home is quite possible, especially in the southern regions and Central Asia. The experience of growing African sharptooth catfish in summer cottages in the Orenburg region has shown that in a metal barrel containing water for irrigation, during a warm period of time it is possible to grow sharptooth catfish from 10 g to 300 - 1000 g. At the same time, food products were used as food for sharptooth catfish waste, insect larvae from the garden, chicken and fish offal, etc. The stocking density of clarium catfish in a summer cottage should not exceed 50-70 fry per tank with a capacity of 2000 liters. Barrels should be stocked with fry during the period when the average daily water temperature is above 15 °C. Thus, growing African catfish in ponds dug in summer cottages is no more difficult than growing fish such as crucian carp, tench, carp, and silver carp in them. 

African catfish roe

 

African catfish roe can also be a commodity. This will help grow clarius catfish cheaper and make the farm profitable. African catfish caviar is a fairly expensive product. Farms that grow white catfish can additionally receive African catfish caviar. Thanks to this, prices for commercial fish can be reduced.

This can be achieved by organizing multiple lifetime receipt of ovulated eggs from female African catfish.

Unlike sturgeon fish, the caviar of the clarium catfish can be expressed not once a year, but much more often. Special experiments have shown that it is possible to stimulate the ovulation of a new portion of eggs in female caviar catfish within a week after the previous pumping. However, the amount of caviar obtained in this case is very small. The optimal period of time between successive caviar collections is considered to be an interval of 4-6 weeks. Thus, you can express eggs from the same female clarius catfish 8-12 times a year.

Ovulation of eggs in female clarium catfish can be stimulated using a wide range of drugs (pituitary glands of fish and amphibians, human chorionic gonadotropin, analogs of gonadotropin-releasing hormones). Moreover, in many cases, just one injection is sufficient to obtain the effect. High friendliness and predictability of maturation are noted.