CATDOLL : CATDOLL: Summarize the types of fish fertilization, reproduction and development?

1. Summarize the types of fish fertilization, reproduction and development?

Fertilization in fish can be external or internal; reproduction can be oviparous, viviparous, or ovoviviparous.

Oviparous: fertilized and developed outside the body. Some species are fertilized inside the body, but the fertilized eggs are hatched outside the body, so they are still oviparous, such as the medaka.

Ovoviviparous: Fertilization and hatching inside the body, the young fish are expelled from the mother as lively ones, but they do not use the mother's nutrition, so it is called ovoviviparous, such as guppy.

Pseudoviviparity: The oviduct of some cartilaginous fish has developed into a structure similar to the uterus of mammals, and is connected to the embryo by blood circulation through a "yolk placenta" structure, supplying nutrients for embryonic development.

The developmental stages of fish: embryonic stage - larvae stage - juvenile stage - young fish stage - adult stage - aging stage.

Development includes embryonic development and post-embryonic development.

2. What are the effects of cigarette ash on fish?

If used properly, cigarette ash can relieve itching, deodorize, and cleanse. Cigarette ash is also plant ash. The ash produced by cigarettes can effectively kill fungi on the surface of the skin and keep the skin surface dry. As for the effect on fish, I really don't know. But it can be assumed that my personal opinion is that a small amount of cigarette ash in the water has no effect on fish. As for a large amount of ash in the water, I don't know because there is no record of such an experiment, but what is certain is that a large amount of cigarette ash will definitely affect the water body. Fish may find it difficult to adapt.

3. Fish that have high requirements for fresh water?

A: Such as trout, sturgeon, bass, knife fish, mandarin fish, stream grouper, etc.

Freshwater fish. Belongs to the genus Salmonidae. There are about six or seven species in the world, three of which, namely rainbow trout, cutthroat trout and Atlantic salmon, are native to Canada; the other two, namely brown trout and golden trout, have also been introduced to Canada. Unlike other salmonid fish, trout have black spots on their heads and bodies, and 7 to 12 fin spines on their tail fins. Except for the golden trout native to California, which only lives in small high-altitude lakes in western Alberta, all other trout species have both marine and freshwater forms.

4. All fish lay eggs, right?

wrong.

5. What is the impact of TDS on fish reproduction?

TDS represents the water hardness index. Too low total water hardness is not conducive to fertilizing the water.

It is not conducive to the growth of farmed animals. In particular, crustaceans (crayfish, crabs, etc.) will have problems such as failure to molt, slow growth, and low molting doubling rate. Total hardness is a very important water quality indicator in aquaculture.

6. What is the impact of El Niño on fish?

Reduce fish

Some Southeast Asian countries have suffered greatly from the threat. It is understood that Laos, Vietnam, Myanmar, Cambodia and Thailand are all facing the threat of salinization of water bodies caused by falling water levels and seawater backflow, which has brought very adverse effects on the aquaculture industry.

7. What are the water temperature requirements of warm water fish? What are the water temperature requirements of warm water fish?

Warm water fish have very high requirements for water temperature. The temperature of warm water must be between 31 degrees and 33 degrees, not too high, otherwise, fish farming will be dangerous and the mortality rate is very high. Because warm water fish are what we often call tropical fish, they require the water temperature to be guaranteed at around 31 degrees, which is the best water temperature. In addition, warm water can also play a certain bactericidal role, so it is also practical for fish farming.

8. What is the impact of development on appearance?

Of course it does! As development progresses, you may look super good or super ugly! The development during puberty is quite troublesome. Usually, this stage is the ugliest, with acne. Because puberty develops quickly and you eat a lot, you may become obese. But some people will be more beautiful than before because of their full development? In general, the development after puberty is more stable. Usually, developing too fast will reduce the appearance, so be moderate!

9. Which milk powder is best for brain development?

1. Milk powder: It is made from milk as the main raw material, which contains rich protein, fat, sugar, amino acids, minerals and other nutrients. Drinking some milk powder properly on a regular basis can help supplement the nutrients needed by the body, enhance the body's resistance, and also improve the operating efficiency of the brain system to a certain extent.

2. Goat milk powder: This milk powder has a relatively high nutritional value. It contains rich small molecule proteins, which are close to breast milk. Drinking some goat milk powder properly will help the body digest and absorb it. It also contains rich nutrients such as amino acids, proteins and calcium, which can promote the development of brain cells and help improve memory.

3. Soy milk powder: It is usually made from soybeans and milk as the main raw materials. It contains rich plant protein, amino acids, soybean lecithin, multiple vitamins, cellulose, trace elements and other essential nutrients for the human body. Drinking soy milk powder appropriately can help strengthen the body and also play a certain role in brain health.

10. What is the effect of gonadotropin on cattle?

Hello HCG features:

1. It has the functions of FSH and LH, maintaining the life of the menstrual corpus luteum and making it enlarge into the corpus luteum of pregnancy;

2. Promote the aromatization of androgens into estrogens and stimulate the formation of progesterone;

3. Inhibit the stimulation of plant lectins on lymphocytes. HCG can be adsorbed on the surface of trophoblast cells to prevent embryonic trophoblast cells from being attacked by maternal lymphocytes.

4. Stimulate the fetal testicles to secrete testosterone and promote male sexual differentiation;

5. It can bind to the TSH receptor of maternal thyroid cells and stimulate thyroid activity.