CATDOLL : CATDOLL: What do crab seedlings eat to grow up: Little crabs actually eat these things

Crab seedlings are the young crabs. Many people like to eat crabs, but many people don’t know what crab seedlings eat when they grow up. Let’s follow me to see what crab seedlings eat.

Crab food

Under natural conditions, they mainly feed on aquatic plants and humus, and are fond of eating animal carcasses. They also like to eat snails, clams, worms, and insects. Occasionally, they also prey on small fish and shrimps. When food is scarce, they will kill each other and even swallow their own eggs. Sometimes, a dead fish will cause competition for food with their own kind. Generally, it is easy for river crabs to obtain plant food, which often constitutes the main component of the crab's stomach food. There is also some mud and sand in the crab's stomach, which is a sign that river crabs feed on benthic organisms and humus.

Crabs are omnivorous animals, they eat everything, such as bread crumbs, rice residues, small fish, shrimps, etc. Wild crabs generally eat some planktonic plants and animals, while artificially raised crabs are mainly fed with special feeds.

Foods that Crabs Eat in Crab Farming

Crabs are omnivorous aquatic animals. Their food sources range widely and can be roughly divided into three categories: natural bait, artificial animal bait and artificial plant bait.

Natural baits are all kinds of organisms that crabs like to eat and grow naturally in water or on land. Natural baits mainly include phytoplankton, aquatic plants, benthic animals, and terrestrial animals and plants.

1. Phytoplankton: including diatoms, golden algae, dinoflagellates, naked algae, green algae, etc., which are feed for early juvenile crabs and zooplankton.

2. Zooplankton: Rotifers, cladocerans, copepods, etc. are good feed for it.

3. Aquatic plants: including Vallisneria, Hydrilla verticillata, Water Chestnut, Potamogeton, Duckweed, Lemna, Water Lettuce, Water Peanut, Golden Grass, etc., are its main natural bait.

4. Benthic animals: Snails, clams, river clams, earthworms, etc. in the water are its best feed.

5. Terrestrial plants and animals: including mealworms, earthworms, ryegrass, wolfgrass, and composite grass.

Artificial animal baits Artificial animal baits mainly include snails, clams, river clams, silkworm pupae, mealworms, earthworms, small fish, maggots, and livestock and poultry viscera.

Artificial plant baits Artificial plant baits mainly include soybeans, bean cakes, vegetable cakes, cottonseed cakes, wheat, rice bran, bean dregs, distiller's grains, sauce residues, peanut cakes, etc.

During the breeding process, you cannot feed only one kind of bait, but should feed comprehensively according to the actual situation. Only in this way can you effectively improve the breeding efficiency of crabs.

How to breed crab seedlings

1. Understand the crab seedling cultivation process

Before purchasing crab seedlings, farmers should first understand the entire production process of the crab seedling farm, mainly including: parent crab specifications, feed usage, cultivation cycle, etc. Parent crabs used for breeding crab seedlings should preferably come from large bodies of water in natural lakes, and female and male crabs should come from different waters to avoid inbreeding. Parent crab specifications: Each female crab should be no less than 125 grams, and each male crab should be no less than 150 grams.

The crab seedlings bred with Artemia (Brine shrimp) have better quality, while the crab seedlings bred with substitute baits such as freshwater fleas and egg yolks have poorer quality.

In addition, the crab seedling cultivation period is generally 19 to 21 days, and the water temperature is around 21°C when the seedlings emerge.

2. Do a good job in identifying the quality of crab seedlings

1. The body color of high-quality crab seedlings is light yellow, shiny and transparent, and there are no foreign objects such as shrunken worms or filamentous bacteria on the body surface under microscopic examination. The body color of low-quality crab seedlings is dull, dark or light, milky white or orange-red, and the crab seedlings are found to be carrying bacteria and worms under microscopic examination.

2. High-quality crab seedlings are strong, uniform in size, phototactic, aggressive in feeding, and have strong ability to swim upstream. The crab seedlings crawl vigorously when touched, and react quickly when blown. Grab a small amount of crab seedlings with your hands, shake off the water, and gently hold them into a ball. They will immediately fall apart when you let go. Poor-quality crab seedlings have an empty stomach and no food, and have poor swimming ability. They tend to move at the bottom of the water body. The crab seedlings that are caught by hand tend to form a ball and are not easy to fall apart.

3. Crab seedlings specifications: Normal crab seedlings out of the pond should be 120,000-140,000 per kilogram, and no more than 170,000. Crab seedlings that reach this specification have fewer pseudo-seedlings and are more likely to become young crabs. If there are too many crab seedlings, it means that the crab seedlings are young and have soft shells that cannot withstand handling and transportation. If there are too few crab seedlings, the crab seedlings are large in size and are close to the molting period. They will molt and die during transportation.

4. Salinity and temperature of nursery water: When the crab fry are taken out of the pond, the salinity of the water is required to be no higher than 4‰, the desalination time is no less than 7 days, the water temperature is around 21°C when the fry emerge, and the temperature difference between the nursery pond and the breeding pond is within 2°C, and no more than 4°C at most.

Cultivation and management of crab seedlings

1. Feeding

After the crab seedlings enter the pond, they are immediately fed with crushed tofu and powdered egg yolk, which are evenly spread on the water surface and the waterside slope. The daily feeding amount is about 3% to 5% of the crab seedlings' weight. In the first two days, they are mainly fed with plant-based baits, and after three days, they are supplemented with fish paste, bone meal, wheat flour, etc., with enough food and a little left over. After 5 days of temporary feeding, they will shed their shells and become first-stage juvenile crabs after 7 days. At this time, the juvenile crabs are light yellow, fresh and tender. After that, they change from floating to benthic life, and the bait changes from paste to paste. The first-stage juvenile crabs have an increased appetite, and the amount of feed is increased to about 6% to 10% of the crab's body weight.

2. Water layer management

When the crab seedlings are put in, the pond water depth is 30cm to 40cm. Shallow water heats up quickly, which is conducive to the decomposition of organic fertilizers and the reproduction of plankton, and is conducive to the molting and growth of young crabs. Add new water after 7 days, and then add water every 4 to 5 days. The amount of water changed each time accounts for 1/3 to 1/2 of the water depth to prevent the loss of fertilizer and water and the change of water temperature from affecting the growth of young crabs. The dissolved oxygen in the water is not less than 5mg/L. In order to increase the fertility and dissolved oxygen of the water, a fertilizer pool can be built at a high place and dripped continuously.

3. Eliminate enemies

When cleaning the pond before stocking, do not use 223, DDT, 666, etc. to remove natural enemies. After stocking, pay attention to removing natural enemies such as frogs, toads, water rats, and water snakes at any time. Ducks are not allowed to enter the pond. Protective and escape prevention facilities must be strictly checked to ensure the safety of young crabs.

4. Climate fusion prevention

During the temporary rearing period, the crab seedlings are immature. If the temperature difference exceeds 5℃, a large number of crab seedlings will die. It is necessary to drain water in time to conserve water, strengthen the shed and crab wall. At the same time, pay attention to the quiet environment that young crabs need to molt to reduce interference with them.

The entire temporary rearing period should be 3 weeks of age, and no longer than 4 weeks of age. At this time, the crab seedlings molt once and molt 4 to 6 times. The back diameter is more than 5mm. The ability to adapt to the natural environment, resist enemies, and forage for food is enhanced. The individuals are large, consume more oxygen, eat more, excrete more, and the water quality is easy to deteriorate. Further temporary rearing is not conducive to their growth, and will form dead crabs, and even kill each other. They must be moved to a sparsely raised large crab breeding pond.

After reading what crab fry eat to grow up, read:

1. What are the living habits of river crabs?

2. What are the techniques for fattening hairy crabs?

3. Crab farming methods

4. How to breed swimming crabs

5. How to farm crabs