CATDOLL : CATDOLL: How do fish grow? What is the fastest growing fish?

1. What is the growth process of fish?

A fish goes through five stages in its life: embryonic stage, fry, seedling, young fish, sub-adult fish and adult fish. The embryonic stage is the very beginning period of the fish, which refers to the time from the fertilized egg to the hatching of adult fish. The newly hatched fish is the fry. After three to five weeks, the fry will grow into seedlings, and then go through the young fish and adult fish stages before finally growing into adult fish.

2. What are the fastest growing fish?

1. Snakehead

Snakehead fish is a common edible fish, also known as mullet, raw fish, fortune fish, snake fish, firehead fish, etc. It mainly grows in still water or micro-flowing water with dense aquatic plants and fine bottom mud. Snakehead fish is a freshwater fish variety farmed in many areas. Generally, it can reach a weight of 0.5-0.7 kg after 8-9 months of breeding. It is a fast-growing fish with high economic value.

2. Black carp

Black carp is one of the four major fish species in my country and is currently being artificially raised in many areas. Black carp mainly grows in the middle and lower waters, and the most suitable water temperature for its growth is 22-28 degrees. It mainly feeds on snails, clams, mussels, clams, shrimps and insects. It grows very fast and can grow up to about 70 kilograms.

3. Grass carp

Grass carp is also one of the four major carps and the most artificially raised fish species in my country. Grass carp mainly grows in the middle and lower layers of water and in waters with abundant aquatic plants. It is a freshwater fish that feeds on grass. Grass carp grows relatively fast, and the largest individual can reach about 40 kilograms.

4. Catfish

Everyone is familiar with catfish, and they are artificially raised in many areas. Catfish mainly live in the middle and lower layers of rivers, lakes, reservoirs, and ponds. They are a kind of freshwater fish with fast reproduction, strong survival ability, and fast growth. Many people don’t know that they can grow 6 kilograms in half a year. They are also a freshwater fish species raised in many areas.

5. Silver Carp

Silver carp, also known as silver carp, mainly lives in the upper and middle layers of water. In winter, the temperature is low, so it will hibernate in deep waters. Silver carp mainly feeds on plankton in the water. It is a typical filter-feeding fish and its growth rate is also relatively fast.

6. Bighead carp

Bighead carp is a kind of fish that many people like to eat. The chopped pepper fish head we often eat is made of bighead carp. Bighead carp mainly lives in the middle and upper layers of water, mainly feeds on plankton in the water, and grows relatively fast.

7. Wuchang Fish

Wuchang fish is a fish that is unique to my country and is produced in the middle and lower reaches of the Yangtze River. It grows fast and has strong disease resistance, making it a very easy-to-breed fish. In addition, Wuchang fish has tender meat and is particularly suitable for steaming. Steamed Wuchang fish is a traditional dish in Hubei Province and is deeply loved by people in Hubei and even the whole country.

3. 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.

4. Observation notes on strawberry growth?

1. Purpose of Practice

I chose common strawberries as the target of experimental observation. By cultivating strawberry seedlings in a transparent container without soil and using a well-proportioned nutrient solution to meet the growth needs of strawberries, I observed the entire process of strawberries from rooting to flowering and fruiting, and recorded the effects of temperature on the branches, leaves and flowering of strawberries during the process. Through this experiment, I deepened my understanding of knowledge, stimulated our interest in scientific exploration, and improved my hands-on ability.

2. Principles of Practice

In the laboratory, we simulated the environment in which strawberries grow and provided strawberry seedlings with nutrient solution, which is composed of water and nutrients in a reasonable ratio. The conventional soil cultivation method is that plants absorb water and inorganic salts and other energy required for growth through their roots in the soil, and fix themselves through the soil. According to this principle of plant growth, we mixed the water and inorganic salts and other nutrients required for plant growth into nutrient solution in proportion, and fixed the plants in a corresponding way to prevent them from falling over, so as to conduct the strawberry observation experiment.

3. Observation and Recording Methods

The experiment adopted the observation and recording method, observing and recording the growth of branches and leaves of strawberry seedlings at different temperatures at any time.

4. Practice Equipment

Soilless flower pots (simple and environmentally friendly flower pots made from canning bottles, etc.), strawberry seedlings, nutrient solution in a reasonable proportion, a balance, clean small stones, a thermometer, etc.

V. Experimentation and Management

1. Test period: September 2017 to May 2018

2. Experimental location: School Biological Laboratory

3. Nutrient solution for soilless cultivation

4. Cultivation methods

Select strawberry seedlings that are free of pests and diseases, in good growth condition, short and strong, with about 5 leaves and full top buds. Clean the soil at the roots of the strawberry seedlings without damaging the roots, fix them in a soilless flowerpot, and use small stones that have also been washed as fixers. Now introduce an appropriate amount of clean water into the pot, wait for about a week, and after new roots grow, pour out the water and replace it with an appropriate amount of nutrient solution.

5. Management Process

(1) Add nutrient solution in a timely and quantitative manner. According to the actual growth situation, add nutrient solution once or twice a week, about 70 ml each time. After April, the weather turns warmer, the temperature rises, the evaporation of water increases, and the strawberry seedlings enter the flowering period. At this time, the demand for nutrients is high, so the time for adding nutrient solution is changed to once every 3 days, and the concentration of the nutrient solution should be increased accordingly to meet the growth needs of the strawberry seedlings.

(2) During the early growth period from September to March, the strawberry seedlings were sprayed with water every other day. After entering April, as the evaporation of plant water increased, the spraying frequency was changed to once a day, so that the humidity of the growth environment of the two groups of strawberry seedlings was maintained at a relatively stable level of around 75%.

(3) The two groups of strawberry seedlings were grown in an environment with natural light, but they could not be placed in direct sunlight to prevent the nutrient solution temperature from being too high, causing the roots of the strawberry seedlings to rot and die.

(4) Prune the plants in time and remove old leaves and branches with growth problems. Especially when yellowing or discolored branches are found, they should be removed in time to ensure the nutrient supply of the trunk and branches with good growth, and avoid excessive consumption and waste of nutrients.

(5) Always pay attention to the situation of pests and diseases. If any pests and diseases occur, deal with them in time to avoid affecting the growth of strawberry seedlings.

(6) Under the guidance of the teacher, after the strawberries bloom, pay attention to pollination and fruit growth.

6. Observation and Recording

The growth of roots, stems, leaves and flowers of soilless strawberry seedlings at different temperatures is as follows:

1. The roots begin to grow new roots at around 7°C, and around 17°C is the most active temperature for root growth. However, when the temperature is higher than 30°C, the roots begin to change color, stop growing, and rot. In winter, when the temperature is below -9°C, frostbite may occur.

2. The stems and leaves of strawberry seedlings begin to grow when the temperature is around 6℃, and grow best at around 18℃. In summer, when the temperature is above 30℃, they will not stop growing and will turn yellow.

3. Entering the flowering period in April, when the temperature reaches above 10℃, the strawberry seedlings begin to bloom, and the flowers bloom most luxuriantly at around 16℃.

4. The pH value of the nutrient solution also affects the growth of strawberry seedlings. A pH value that is too high or too low will cause the strawberry seedlings to grow slowly or even stop growing. The most suitable pH value is around 6.8.

VII. Results and Experience

During the experiment, I observed the appearance of new roots growing from the roots of plants, and saw the whole process of strawberry seedlings growing slowly from seedlings, gradually growing flower buds, then blooming and bearing fruit. Through observation, I learned about the whole process of strawberry production, and also understood why plants do not grow in winter, and knew at what temperature in spring the plants would begin to grow new leaves, bloom flowers, and bear fruit. At the same time, in the process of caring for the growth of strawberry seedlings, I also learned a lot of knowledge about plant growth, such as paying attention to the treatment of old leaves and excess branches and stems to ensure the normal growth of plants.

5. How to observe the growth of hairy crabs?

To observe the growth of hairy crabs, you should first place them in a certain area and let them grow freely, and then observe them at irregular intervals every day.

6. What kinds of fish can grow in dark environments?

Fish that live in dark environments - cave fish.

The basic characteristics of cave fish are: eyes are reduced or disappeared; the body is without pigment, in a translucent state, and the internal organs are vaguely visible; the scales are smaller, sparsely arranged or completely buried under the skin; the sense of touch is sensitive, the tentacles are well-developed or have derived sensory organs. These traits are called convergent characteristics in biology. The disappearance of their eyes is not caused by trauma or pathology, but the result of high adaptation to the environment, and can be inherited to the next generation. Cave fish are also called blind fish, eyeless fish, and transparent fish. They have developed a unique physiological structure to adapt to the environment because they have lived in a dark environment for a long time. Admittedly, their value cannot be measured according to traditional edible or delicious standards, but as examples of biological adaptation to the environment, they are rare treasures in museum displays or intuitive teaching.

The ancestors of cave fish are no different from the fish we see today. It is only because they strayed into an underground river and lived in darkness for a long time that they underwent great physiological changes to adapt to the changes in the environment. Moreover, they were able to pass on these changes from generation to generation, thus forming a biological species.

7. What are the fish that grow at low temperatures?

How low is the so-called low temperature? If it refers to wide-temperature fish, that is, most of the fish that can spend the summer and winter outdoors in China, such as the Chinese croaker, striped barbel, the most beautiful tetra, white-faced shrimp, Sichuan shrimp, garfish, dogfish, etc. If it refers to low-temperature fish, that is, fish that cannot survive in hot water, there is the plateau schizothorax, which is generally found in western Sichuan, and some cave fish are also low-temperature fish. The water does not freeze.

8. What are the growth characteristics of fish in Baiyangdian?

The growth characteristics of fish are:

1. Continuous growth: fish can continue to grow throughout their lives until they age and die;

2. Staged growth: fast growth before sexual maturity and slow growth after sexual maturity. Before sexual maturity, the main manifestation is a significant increase in body length, after sexual maturity, the length growth decreases and the weight growth increases. During the aging period, the growth of body length and weight decreases sharply.

3. Seasonal growth: rapid growth in spring and summer, and slow growth in autumn and winter. Understanding the above growth characteristics of fish can help us determine the breeding cycle of fish and choose the period of rapid growth for breeding; determine the fishing specifications of fish; timely catch and market individuals that have exceeded the rapid growth period to reduce the food consumption of the water body; and take effective breeding measures in the spring and summer when fish grow rapidly to accelerate fish growth.

9. In which season do fish grow fastest?

Summer and autumn.

The peak season for fish growth is generally from June to September each year. During this period, the water temperature is suitable, bait and fertilizer are sufficient, and fish eat vigorously. It is the golden season for fish growth. However, it should also be noted that due to the high temperature, fish are prone to disease.

However, due to the large latitude span between the north and south of my country, the corresponding temperature and seasonal changes are quite different, and the growing season lengths vary. For example, compared with the Yangtze River Basin, the north is generally delayed or advanced by about one month.

10. The longer the photoperiod, the faster the fish grow?

All things cannot grow without light, and fish are no exception. The color change of fish is the result of light; the healthy growth of fish also depends on the help of light. Therefore, if you want to keep fish healthy and beautiful, you must let them receive light. The light here includes both sunlight and artificial light in the home.

Tropical fish are very sensitive to sunlight.

The same tropical fish will show different colors when living in a strong light environment and a weak light environment. The color depth of many tropical fish is closely related to the light intensity.