How old are loach eggs? How many eggs can you lay at once?

Misgurnus anguillicaudatus, known as "ginseng in water", has high breeding value. Natural reproduction refers to imitating natural environmental conditions under artificial control conditions, allowing Loach to lay eggs and hatch on its own. So how old is the Loach to lay eggs? How many eggs can you lay at a time? Next, let's learn about it together.

How big is the Loach to lay eggs?

Misgurnus anguillicaudatus matured at the second instar and began to lay eggs. The mature female Loach has a round belly and smooth pectoral fins, and the individual is larger than the male Loach. The reproductive period of Misgurnus anguillicaudatus is usually from April to August. It is the peak spawning period from late May to late June when the water temperature is about 25 ℃.

Misgurnus anguillicaudatus is a multi-spawning fish. Under natural conditions, reproduction began in early April, the peak spawning period was from May to June, and spawning lasted until September. The water temperature of breeding is 18-30 ℃, and the optimum water temperature is 22-28 ℃. The sexual maturity of the female Loach is later than that of the male Loach. When the body length is 5 cm, the female Loach has a pair of ovaries. When the body length is 8 cm, the two ovaries heal together and become one ovary, which extends from the front end to the back end, and the whole ovarian development begins to mature. The fecundity of female Loach varies greatly with individual size. The minimum number of sexually mature individuals is 8 cm in length, about 2000 eggs, 7000-10000 eggs in 10 cm, 12000-14000 eggs in 12 cm, 15000-18000 eggs in 15 cm, and 24000 eggs in 20 cm. The largest number of eggs can be more than 65000. Oval, egg diameter of 0.8-1.0 mm, swelling to 1.3-1.5 mm after water absorption, egg yellow, semi-sticky, adhesion is not strong. Due to the inconsistent maturity of eggs in the ovary, the amount of ovulation per ovulation is about 50% to 60% of the number of eggs conceived. The male Misgurnus anguillicaudatus has a minimum sexual maturity of more than 6 cm, and the sexual maturity is earlier than that of the female Loach. A pair of male Loach testis, located on both sides of the abdominal cavity, are banded and asymmetrical. The testis on the right side is longer and narrower than that on the left, and the weight is lighter. When the male Loach is 9-11 cm long, there are about 100 million sperm in the testis.

Misgurnus anguillicaudatus lays eggs in the sunny morning after rain, and the female Loach swims in front of it before spawning. Several males follow closely. During estrus, females and males mostly move on the water surface and around the fish nest. When the estrus reaches the most exciting part, the head and body of the female and male Loach rub against each other and swim out of the water one after another. The male Loach chases the female Loach and curls it in the belly of the female Loach to stimulate the female Loach to lay eggs. At the same time, the male Loach also produces sperm for in vitro fertilization, which varies according to the individual size, and the individual size can be more than 10 times. The fertilized egg first adheres to aquatic plants or other attachments, and with the fluctuation of the water, it is easy to fall off from the attachment and sink to the bottom of the water.

How many eggs can you lay at a time?

1. The relationship between the number of eggs laid and age and body length: the number of eggs laid by Misgurnus anguillicaudatus was different with different ages and different body length. The relative fecundity of female Loach with body length of 15.1 cm to 20 cm and more than 20 cm was twice as high as that of 10 cm to 15 cm. After hormone injection, the fecundity of Misgurnus anguillicaudatus of different ages was significantly different, and the fecundity of 4-5-year-old was significantly higher than that of 1-3-year-old, about 2.2 times. The relative fecundity varied at 22 eggs per gram.

two。 The relationship between reproductive effect and water quality:

(1) pH: fish are very sensitive to the change of pH in water. In the water of pH5.6~9.0, Misgurnus anguillicaudatus can lay eggs, and the number of eggs laid is basically unaffected. However, below pH6.5 and above 8.5, it had obvious effects on the fertilization rate of Loach eggs and the hatching rate of Misgurnus anguillicaudatus seedlings, especially on the hatching rate. The pH of breeding water environment is 7-8, that is, neutral or slightly alkaline.

(2) Light: Misgurnus anguillicaudatus likes to drill mud, lives at the bottom, and is less sensitive to light. The results showed that no matter what color the light was, there was no significant difference in the reproductive effect of Loach.

(3) Water temperature: Misgurnus anguillicaudatus has a good reproductive effect in the range of water temperature 18 ~ 26C, especially when the water temperature is 20 ~ 26C. Below or above this range of water temperature, the reproductive effect is greatly affected. For example, when the water temperature is 16 ~ 18C, the spawning rate is only 25%. The fertilization rate is 30% and the hatching rate is 20%. When the water temperature is 20% 26C, the spawning rate is I00%, the fertilization rate is 89% 92%, and the hatching rate is 72% 77.4%.

(4) the relationship between the adhesion of fish eggs and fish nest materials: Loach lays slightly sticky eggs, and two kinds of fish nests are made of brown slices and aquatic plants. The situation of adherent eggs and the fertilization rate and hatching rate of Loach eggs were observed to explore the requirements of artificial nest materials for Loach spawning. The results showed that there was no significant difference in fertilization rate and hatching rate between the two kinds of fish nest materials. However, there was a great difference in the number of eggs adhered to the Loach, and the number of eggs attached to the brown fillet nests was 4 times higher than that on the nests of aquatic plants.

Three ways of reproduction of Loach

1. Natural spawning reproduction

Parent Loach was placed in the spawning pond. When the water temperature rose above 18 ℃, sterilized brown slices, willow roots and aquatic plants were placed in the pond as fish nests. After it is found that Loach lays eggs, the nests that have already laid eggs are transferred to the hatching pond, and at the same time, they are put into the new nests, waiting for them to lay eggs again. The hatching of fertilized eggs does not require high water temperature, which can be hatched in general aquaculture water. The optimum water temperature is 20 ℃ ~ 28 ℃, and the fish can hatch in about 2 days.

two。 Artificial induced reproduction

When the temperature is suitable from April to May, the parent fish with soft belly, slightly pink color and near the sign of spawning should be caught, whose body length is 12cm, weight is more than 20g, and the best individual is about 40g. The dose of each female Loach can be PGl or LRH-A5-10 micrograms of common carp, and the dose of male Loach can be reduced by half. Then the parent Loach after induced spawning was put into the spawning pool and allowed to spawn and fertilize or artificially fertilized. Finally, the fertilized eggs are nestled into the incubator to hatch. This method can obtain a large number of Loach seedlings on time and in a planned way.

3. Seeding and supplementary reproduction

This is the easiest way to reproduce. That is, to put an appropriate amount of mature Misgurnus anguillicaudatus in the water body of Loach, but not to raise other fish first, and to place some artificial nests in the reproductive season. Loach lays eggs in the culture pond, hatches in the original pond, and the seedlings can be cultivated in a small box, and then still raised in the original pond.