How to Raise Frogs: Breeding Methods and Key Technical Points

Everyone is very familiar with frogs. In the countryside, when it gets especially quiet at night, you can always hear waves of frog calls outside the window. Frogs catch pests in the rice paddies, but because people discovered that their meat is very delicious, they became a delicious dish on the dining table.

Frogs' Living Habits  

Frogs inhabit the grassy banks of ponds, ditches and small rivers, and rice paddies, preying on insects, mainly agricultural pests. Adults live an amphibious life on land and in water. During the day they generally hide in grass or rice paddies, and come out to activity at night and in the early morning. When the air temperature drops below 10°C, frogs burrow into the water's edge or soil to hibernate, and emerge the following spring (early March in the Yangtze River basin). They generally breed from April to July. A female frog can lay 34 eggs at a time, and the fertilized eggs can hatch into tadpoles in 12 days. After growing to a certain degree, the tadpoles begin metamorphosis.  

Construction of Frog Breeding Ponds  

Frog breeding ponds are divided into spawning ponds, tadpole ponds and adult frog ponds. Generally, a damp, warm and shaded place should be chosen, and a long cement pond or earthen pond is suitable. For a large outdoor pond, 4×6 m makes one single pond. The pond walls are best plastered with cement, while the bottom should still be left as soil; for a small courtyard pond, 1×1.5 m to 2 m is suitable, generally 1 m deep, with an inlet hole and a drainage channel, and a water depth of 20-50 cm. A shade board must be set over the pond surface. Generally, 40 adult frogs can be raised per sq m. Frog breeding ponds can use earthen ponds, brick ponds or rice paddies, and the key lies in preventing escape. If conditions permit, a brick wall can be built, or netting can be used, generally 1-1.2 m high. The water depth in the pond is 30-60 cm. In the middle of the water or on the sunny side, a mound of soil is piled up as land habitat for the frogs, accounting for about 1/3 of the whole pond. Grass or crops are planted on the mound. A small amount of floating aquatic plants is put into the pond water. For ponds used to raise tadpoles, only a small area of land is left for the young frogs to come ashore after metamorphosis. A cement pond is better for tadpoles, and the pond wall slope should be gentle to provide habitat for the tadpoles. 

Feeding and Management of Frogs  

1. Feeding and Management of Tadpoles  

For artificial rearing of edible frogs, they must be raised and hatched from artificially collected eggs. After emerging from the membrane, the tadpoles are reared in the original hatching pond or net cage, with 600-800 tails stocked per sq m of water surface. On the 4th day after hatching, artificial feeding begins. After about one week of rearing, the tadpoles are moved into the rearing pond. After about 20-30 days, they gradually take red worms, water fleas and fly maggots as their main food, and can also take soybean milk, soybean residue, soybean cake powder and chlorella as their main food; adding a certain amount of fish meal can promote their growth. Generally, for every 10,000 tails, 15 cooked eggs are crushed and sprinkled with water for feeding 1-2 times. After the 5th day, switch to a mixed feed of soybean milk, wheat bran and tofu residue, or feed such as rice bran and fish meal, put in 1-2 times a day. The feed is placed on a feeding platform; powdered feed is first mixed with water into a thick paste and then sprinkled for feeding.  

Tadpole management: when bubbles are found in the pond water or the water quality has a rotten smell, replace it with fresh water immediately, generally once every 3 days. In dry weather with many consecutive days of high temperature, change the water once every 2 days.  

Metamorphosis management: about 70 days after the frog eggs hatch, they become young frogs. In the stage from the appearance of the forelimbs to complete metamorphosis, the tadpoles mainly rely on absorbing the supply from the tail, breathe air with their lungs, and begin to leap out of the water to come ashore for habitat. When more than 90% of the tadpoles have become young frogs, they can be moved into the young frog pond for rearing.  

2. Feeding and Management of Young Frogs  

Intensive domestication: high-density concentrated enclosure rearing can be used at a density of 100-150 frogs per sq m, kept in a cement pond with smooth inner walls and a height of more than 1 m, with a water depth of about 20 cm. A feeding platform is placed on the water surface, and no land is provided in the pond, forcing the young frogs to come onto the platform to feed and rest together.  

Bait domestication: first feed live bait for 1-2 days. On the 3rd day, begin adding 20% artificial feed to the bait, then increase the proportion day by day, and after 10 days increase it to 80%. "Live bait" mainly includes earthworms, fly maggots, small fish and shrimp, insects, snails and loaches; "dead bait" refers to dried silkworm pupae, animal offal and compound feed, etc. Use movement to carry stillness, "activate" the "dead bait", and finally transition to completely feeding on artificial bait. At the same time, feeding must be timed, quantified and fixed in location. Feeding time: in spring and autumn around noon, in summer in the evening or morning, 1-2 times a day, and each feeding should be finished by the young frogs in about 1 hour. For young frogs weighing less than 50 g, the feeding amount should account for 6-8% of body weight; for young frogs weighing more than 100 g, the feeding amount should account for 8-10% of body weight. The bait is required to be fresh, clean and nutritious.  

Screening, grading and separate rearing: when the young frogs have been domesticated for 20-30 days, the pond water should be drained, and the large-sized young frogs should be transferred to the adult frog pond at a density of 60-80 per sq m; the small-sized young frogs remain in the original pond for domestication. Using feed and indoor three-dimensional, multi-layer box and cage intensive breeding is a new method of frog farming. Raising frogs in plastic boxes and wooden boxes for small-scale farming gives an extremely high yield, with several hundred frogs per sq m. Generally, from hatching to adult frog takes only 5 months.  

3. Feeding and Management of Adult Frogs  

After young frogs are transferred into the adult frog pond, the frogs have a large food intake and their growth speed accelerates. This is an important period for forming commercial yield. In addition to supplying sufficient bait, when tadpoles metamorphose into frogs, animal feed must be added, mainly live bait with high protein and high reproduction rate such as artificially cultured fly maggots, earthworms, red worms and chlorella water fleas. When live bait is insufficient, mixed feed can be used, such as 60% rapeseed cake (powdered), 30% rice bran (or wheat bran), 5% soybean powder and 5% fish meal, mixed evenly, with good results. Tadpoles are active in the water, and after 5 days they can be given fine feed, namely soybean milk, egg yolk, water fleas, water spinach, tomatoes and aquatic plankton. In addition, if earthworms are raised on the soil mound, as long as some limewater at a concentration of 3-5% is sprinkled in sections on the mound every evening, the earthworms will come out in full force and serve as frog bait. A proper amount of compound feed should also be fed, and timely separate rearing and adjustment of stocking density are required. After adult frogs are raised for 1 month, when the frog body weight reaches 100 g, the rearing density is 30 per sq m, and after 2 months it is changed to 10-15 per sq m. After a short period of further rearing, they can become commercial frogs for market.  

Frog Breeding Techniques  

The key to frog rearing technology is artificial breeding, because wild field frogs often have a parasite called diplostomulum larvae parasitic in the frog's muscles. Using the method of artificial egg laying and isolating adult frogs can effectively prevent this disease. Stock at a density of about 1 group of breeding frogs per 3 sq m (stocking before May is better). Breeding frogs are required to be large in size, and parent frogs that have been spawning for 1-2 years are best. The mixed stocking ratio of females to males is 3:1, and the stocking density is relatively lower than that of meat frogs. It takes about three years from young frog to sexual maturity.  

Breeding frog management: strengthen the feeding of protein feed, mainly earthworms, supplemented by moth-attracting worms. Maintain the normal balance value of the pond water, requiring it to be fertile and lively. When the water temperature stabilizes at around 22°C, preparations for spawning and hatching should be made (at this time the male frogs croak incessantly). Female frogs over 50 g can lay many eggs at a time. Generally, male and female frogs in amplexus lay eggs on aquatic plants. Frog eggs are light yellow, round, and attached in patches to the gelatinous egg membrane floating on the aquatic plants, very easy to identify.  

1. Spawning: an artificial spawning ground needs a still-water area. Generally, the cage spawning method is used, that is, forcing the frogs to spawn in baskets or cages. With a female-to-male ratio of 1:1, 5 spawning baskets or cages can be placed in a 20 sq m spawning area. The pond water depth should be kept at 10-15 cm, and the water temperature should be kept at 10°C-11°C. In order to increase the hatching rate, the egg patches can be protected with a surrounding net to prevent the parent frogs from disturbing them and making them sink.  

2. Hatching: during the hatching period, the temperature of the fertilized frog eggs should be kept at 20°C-28°C, mainly natural hatching; the plastic film mulching hatching method and the waterless hatching method can also be used. Generally, after 3-5 days all the tadpoles can hatch. Newborn tadpoles depend on the egg membrane to survive safely, so do not stir the pond water casually. After all the frogs have spawned, remove the frogs from the pond at once to avoid interfering with hatching and the tadpoles' living environment. After the eggs hatch for 5 days, fine feed can be provided, such as soybean milk, egg yolk, water fleas and aquatic plankton, fed twice a day, but the amount of bait should not be too much, to avoid water quality deterioration causing tadpole death. After the tadpoles are reared for 1 week, they can be moved into the rearing pond for rearing.

Precisely because frogs are not only a delicious dish but also have the effect of catching pests, many people have begun to farm frogs. We all know that frogs change from eggs into tadpoles, and then the tadpoles gradually become frogs. At different stages, the growth environment and management they need are different.