CATDOLL : CATDOLL: What are the reproductive characteristics of fish? What is the concept of fish reproductive cycle?

1. What are the reproductive characteristics of fish?

Most fish are dioecious, and chase, lay eggs, ejaculate, and hatch when they reach sexual maturity. The feeding habits of fry are different from those of adult fish, and gradually become the same as they grow up. Some fish are fertilized and develop in vivo, and female fish give birth to small fish directly, which is ovoviviparous or pseudoviviparous.

The eggs of some cartilaginous fish and a few bony fish are not only fertilized in vivo, but also develop in the oviduct or ovarian cavity. The embryos are well protected by the mother, and the reproduction of these fish is generally not restricted to a specific breeding site. The oviparous female must expel the eggs from the mother's body, and they can only meet the sperm expelled by the male in the water to complete fertilization and embryonic development.

2. What is the concept of fish breeding cycle?

Ordinary fish can ovulate in spring when the water temperature reaches above 20 degrees. However, different fish have different breeding times. For example, carp spawns from March to August, with the peak period from April to June. Grass carp spawns from early May to early June, with the peak period in mid-to-late May.

3. How do fish reproduce through sowing?

After the fish chases its tail, it will generally lay eggs in three or four days. Usually during the breeding season, male and female fish will mate, and after successful pairing, they will chase each other. This is the fish trying to mate, so after a few days, the female fish will lay eggs, and the male fish will fertilize them. After obtaining the fertilized eggs, the parent fish are usually removed from the tank to prevent them from accidentally eating the eggs and affecting the hatching of the fry.

4. Fish farming technology?

1.

Stocking time selection: Fish should be released on sunny days when the temperature is not too low. Generally, the temperature should be between 2℃ and 5℃. At this stage, the fish scales are tight and the activity is small. It is not easy to injure the fish during fishing, transportation and stocking operations, which can reduce the morbidity and mortality of fish. It is easy to frostbite the fish on rainy days with low temperature or snowy, frozen and windy weather; when the temperature is too high, the fish scales are loose and the activity is large, which is easy to injure the fish during operation.

2.

Stocking of fish: Before stocking the fish, check whether the drugs have lost their effectiveness after pond cleaning. In early spring, the water temperature is low and the toxicity disappears slowly. Water should be taken in advance and test fish should be released. According to the stocking plan, individual size, density, and matching species and specifications, the fish that can be released at one time should not be released in batches, so that the fish can adapt to the environment, start eating early, and promote growth. At the same time, [Gold Iodine] should be used for drug disinfection when stocking fish.

3.

Feeding at the right time When the water temperature rises to 810℃, fish begin to eat, and the amount of food intake gradually increases with the increase of water temperature, so they should be fed in time. Feed once a day or every other day, and choose to feed at noon on a sunny day; as the water temperature continues to rise, the number of feedings can be increased to twice, that is, feeding once in the morning and once in the afternoon. Feeding should adhere to the principle of four determinations (timing, quality, positioning, and quantity), and the specific daily feeding amount should be flexibly controlled according to the weather, water temperature, and the feeding situation of fish. For grass carp weighing more than 1 jin, it is recommended to feed Da Beinong high-grade expanded feed 8103 in the early stage of feeding; for small grass carp mode, it is recommended to feed Da Beinong microecological juvenile fish special feed [Intestinal Liver Health], and the feeding rate is controlled at about 0.5%1%. This product is rich in nutrients and probiotics, which can quickly repair the fish intestines, restore the physique, and improve immunity.

5. Fish that reproduce asexually?

Asexual species such as the Amazon sailfin perch generally use gynogenesis to reproduce, and all offspring are "clones" of their mother. In order to develop embryos, female Amazon sailfin perch will mate with males of similar species, but they do not use the male's sperm, so in theory the offspring will not inherit any genes from the father.

Scientists believe that if sexual species reproduce asexually, they will develop genetic defects and eventually become extinct after a few generations, so the Amazon sailfin perch should have become extinct long ago.

According to mathematical models established by scientists, this asexual female fish should have become extinct 70,000 years ago, but today they still reproduce in southeastern Texas and northeastern Mexico.

What allows the Amazon sailfin perch to survive? Researchers at the School of Biological Sciences at the University of Edinburgh in the UK believe that it is a genetic "trick" that helps the Amazon sailfin perch survive. They may have obtained some DNA from male fish of other species to trigger reproduction and update their own gene pool.

Dr. Lawrence Levy said the study of the Amazonian sailfin perch may also help better understand the survival secrets of other species that reproduce in a similar way. One of them is the salamander, which has been thriving on Earth for more than a million years.

6. How do fish reproduce?

Evolution means having many children, each with slight differences (mutations), and then those that adapt to the environment survive, reproduce, and pass on their genomes.

In the example of the fish biting the hook, the fish that are curious and less vigilant are selected and killed. In this way, the less curious and more vigilant fish are more likely to survive and give birth to offspring. The proportion of fish that are not easily caught will increase in the next generation.

If fishermen kill enough individuals, selection may be complete within a single generation!

In fact, because there are no restrictions on personal recreational fishing, many non-migratory fish in China's coastal waters have evolved and become more cautious in the past 10 to 20 years. Everyone feels that it is becoming increasingly difficult to catch fish.

Similarly, in North America, fishing has never been very difficult because of the restrictions on the amount of fish caught by sports fishing licenses. Fish that are wary or curious about the food that is brought to their mouths have the opportunity to reproduce, and both genes will be passed on to the next generation. Intuitively speaking, fish are more "stupid".

But of course these fish that don't bite the hook don't "know", they are just more picky and more easily frightened. As for understanding the meaning of "fishing line" and "trap", they need to evolve consciousness first, and that may never happen.

peace out.

7. What is the best fish breeding ranking?

Mary, water temperature is 25 degrees, one nest per month|||Red sword, high fin red sword, black sword, apple sword, yellow Mary, white Mary, black Mary, zebra, tiger skin, red sun, golden dragon, red moonlight, red tail golden moonlight, black moonlight, blue moonlight, tricolor moonlight, etc.|||If you practice the breeding skills well, any fish will not be a problem.

Good breeding and raising are relative. It is easy to raise a fish, but it is not easy to raise it well. Even guppies have different strains. Mary, Red Ball, Red Sword, Panda. They are all fish with strong breeding ability.

8. How to prepare fish reproductive hormone?

A mixture of dioxin maleate, luteinizing hormone-releasing hormone analogs and chorionic gonadotropin was used as an oxytocin hormone. Ethylenoxetine and edible oil were added to physiological saline to make an immersion solution for soaking loach parents. The immersion solution temperature was controlled at 21-29°C and the immersion time was controlled at 0.5-8 hours. The oxytocin rate could be controlled at 20%-100%.

9. How do fish reproduce?

There are two main ways:

1. Ovoviviparous fish

Their way of conception is direct internal fertilization, and the female fish can also become pregnant and give birth to small fish directly, such as the ornamental fish such as guppies, red arrowfish, mollies, breams, etc. If we don’t observe carefully, we really can’t find that they will also have such behavior.

2. Oviparous fish

The reproductive method of oviparous fish accounts for a large proportion of the fish's conception methods.

Most of them need an attachment for the eggs, and then the female fish lays eggs on the attachment and the male fish fertilizes the eggs. After a certain incubation period, the eggs can hatch into small fish fry.

10. What are the reasons for fish growth and reproduction?

1. Oviparous. This is the reproduction method of most fish. The fish expel the eggs from the body, and the embryos develop completely outside the body. The nutrients are provided by the eggs and have nothing to do with the mother's nutrition.

2. Ovoviviparity: The fertilized egg develops in the mother's reproductive tract, and its nutrition is provided by the yolk, which has nothing to do with the mother's nutrition.

3. Viviparity. The fertilized eggs of some fish develop in the mother's reproductive tract, and the embryos are connected to the mother's blood circulation. The development of these embryos is not only nourished by the yolk, but also related to the mother's nutrition.

Extended information: In order to breed excellent fry, you must choose healthy broodstock with excellent color, fins and size for breeding. Special care, close attention to water quality changes, live bait, or occasional feeding of fish grass can breed the best fry. Some fish have special requirements for water quality conditions when breeding. Be careful to prevent broodstock from swallowing their own eggs or fry. Fish lovers can estimate the number of fry based on the smooth spawning situation and provide enough food for the fry.