CATDOLL : CATDOLL: Why do fish grow slowly when water temperature is low?

1. Why do fish grow slowly when water temperature is low?

This is because, living in cold water, fish have less activity and slower metabolism, so their growth rate is much slower than warm water and hot water fish, and their growth cycle is generally 1 to 2 years. Cold water fish is a high-quality edible fish with high protein, high unsaturated fatty acids and low cholesterol. 1. The relationship between water temperature and fish body temperature

Water temperature plays an important role in the survival conditions of fish. Fish are cold-blooded animals. The body temperature of most fish differs from the surrounding water temperature by 0.1-1.0℃. Therefore, when fry or adult fish change their environment, temperature stress should be considered.

2. Effect of water temperature on fish gonad development and spawning

The time when mature tilapia and Taiwan loach start spawning is mainly determined by the water temperature. Although the time when spawning starts varies greatly between the north and south, the water temperature is not much different, and generally starts spawning above 23-25℃.

3. Water temperature is related to dissolved oxygen content, which indirectly affects fish

The dissolved oxygen content of the pond decreases as the water temperature rises. For example, under one atmosphere, the dissolved oxygen saturation at 0°C is 14.62 mg/L, and at 20°C it is 9.17 mg/L. However, rising water temperatures increase the metabolism of fish, speed up breathing, and increase oxygen consumption. Coupled with the effects of other oxygen-consuming factors, the pond is prone to hypoxia, which affects the fish. For example, cold-water rainbow trout has a high oxygen consumption rate and requires a higher dissolved oxygen content, and is not adapted to higher water temperatures. One of the reasons is that the dissolved oxygen in higher temperature water is lower.

4. The impact of water temperature on the living environment of fish

Water temperature not only directly affects the survival and growth of fish, but also indirectly affects fish through the change of water environment conditions by water temperature. Almost all environmental factors are restricted by water temperature. Air temperature has seasonal and diurnal changes, and water temperature also has seasonal and diurnal changes. This is a well-known law. Since water is a poor conductor of heat, it transfers heat very slowly from top to bottom. The vertical difference in water temperature between the upper and lower water layers is very obvious, generally reaching 2--5℃. Therefore, the density of the upper and lower water layers is different, and density flow is formed, so that the water body flows up and down by itself, that is, water movement. During high temperature periods, if the weather changes suddenly, such as sultry, thunderstorms, etc., at night, the surface water temperature drops quickly, which will form a strong density flow, driving the decayed matter at the bottom of the pond to float up. A large amount of decomposition consumes the dissolved oxygen in the pond or produces toxins, which will cause fish to float and flood the pond, directly affecting economic income and benefits.

2. Which fish farming requires heating?

The most common small fish on the market, such as tiger barbs, kissing fish, black skirt fish, colorful skirt fish, zebra fish, and tetras, all need heating, and their water temperature should be kept above 20 degrees. As for the scavenger fish, don't think that they are so resistant to low temperatures. There are also issues of different physiques and tolerance of fish, so the water temperature of the cleaner fish must be at least above 16 degrees.

3. Which countries prohibit the breeding of fish?

At present, there are no accurate regulations to prohibit the breeding of fish. Piranhas, gars, and pufferfish are all banned from sale. Generally, the ban is a local regulation. The reasons for the ban are 1. Fish involved in pollution, pesticide residues or heavy metal pollution, etc. 2. Ferocious fish, such as piranhas, are gradually forming a scale in the ornamental fish market, so it is banned to breed gars. Although they are vicious and poisonous, they have not formed a breeding scale. At present, they are only listed as dangerous fish. The blood and ovaries of pufferfish are highly toxic and are listed as banned fish, but there seems to be no regulations for breeding them for fun.

4. What are the farmed fishes in Rongcheng?

Rongcheng's sea is located at the intersection of cold and warm currents, and is recognized by the world as the most suitable latitude for the growth of marine life. Rongcheng's marine aquaculture started in the 1950s, grew in the 1970s, developed in the 1990s, and took off in the early 21st century. It has experienced five industrial waves of "fish, shrimp, shellfish, algae, and ginseng".

5. What is suitable for breeding when the water temperature is low?

(1) Changes in pond water temperature. The water temperature of a pond changes with the temperature, just like other water bodies. However, the magnitude of the change in pond water temperature is much smaller than that of the temperature. The average water temperature during the day is higher than the temperature. The average water temperature during the day is generally lower than the average temperature, while it is higher than the temperature at night.

Judging from the changes during the day and night, the water temperature is generally highest between 14:00 and 15:00, which is later than the highest air and ground temperatures, and the water temperature is lowest in the morning before sunrise.

(2) The impact of water temperature on farmed fish. Different aquatic organisms have different requirements for water temperature. For example, tilapia dies below 131°C, and the four major carps die below -It. Water temperature directly affects the metabolic intensity of fish, thereby affecting their feeding and growth.

All kinds of fish have a suitable temperature range. Generally, within the suitable temperature range, as the temperature rises, the metabolism of the fish will be correspondingly enhanced, the food intake will increase, and the growth will also be accelerated; water temperature affects the development of the fish's gonads and determines the period when spawning begins; the dissolved oxygen content in the pond decreases as the water temperature rises. As the water temperature rises, the metabolism of the fish is enhanced, the respiration is accelerated, and the oxygen consumption increases, so the pond is more prone to hypoxia.

(3) Improvement of water temperature conditions.

When the water temperature is low in spring, shallow water should be used to irrigate the fish pond, which is conducive to raising the water temperature of the pond; tall trees should not be planted near the pond, and emergent plants and floating-leaf plants should not grow in the pond to avoid blocking the sunlight and affecting the water temperature; water with lower water temperature should be passed through a longer process or stored in a water tank for a period of time before being injected into the pond to raise the water temperature; underground hot spring water or factory warm drainage water can be used to raise the water temperature in places with conditions.

6. What are the fishes that are low in purine?

Fish low in purine mainly include the following:

First, freshwater fish, such as carp, crucian carp, grass carp, etc. These fish usually live in clear freshwater environments and do not ingest too much purine substances, so they contain lower purines.

Second, marine fish with low purine content include sea bass, cod and salmon. These fish live in the ocean and have a wider range of food sources, so the purine content is relatively low. It should be noted that there are certain differences in the purine content of different types of fish. For example, crustacean seafood such as shrimp and crab has a high purine content and should be avoided as much as possible. At the same time, purine content is not the only factor that affects physical health, and you should choose the right food according to your own situation.

7. Which fish species are suitable for breeding using the pig model?

It is feasible for some omnivorous crucian carp, carp, etc., and increasing the plankton content by fertilizing the water with manure can help the growth of silver carp and bighead carp. Basically, it can be used, but it should not be used for fish with higher water quality requirements, such as rainbow trout and mandarin fish.

It is best to use it to fertilize the water after cleaning the pond. During the breeding period, try to control it to avoid deteriorating the water quality.

8. What are the morphological characteristics of farmed fish?

Ancient warship

The ancient warship is a very common edible fish in Southeast Asia, its country of origin, but in my country, many fish lovers also raise them as ornamental fish. Since the ancient warship is very common and widely raised in Southeast Asia, fish lovers do not have to worry about their source.

1. Appearance characteristics

The ancient warship is a super strong fish species. And it grows very quickly. It can grow very large in a very short time. So you should be careful not to keep them in a small aquarium. The aquarium should be no less than 120 cm. Otherwise, it will have an adverse effect on their growth.

2. Reproduction characteristics

The reproduction method of the ancient warship is the same as that of the Siamese fighting fish. It also lays eggs in a bubble nest. The male fish is responsible for the protection of the eggs and young fish. The young fish that have just started to swim can immediately eat larger baits such as water lice and silk earthworms due to their large size. It should not be difficult to raise them. The young fish are quite aggressive. At about 2 years old, the ancient warship reaches maturity and can reproduce the next generation. This fish has a certain aggressiveness and is too large. Therefore, it can only be raised with large fish. In the process of raising ancient warships, an albino variety appeared, which is the golden warship. It is also called the fortune-bringing fish. In addition, the scientific community has disclosed two subspecies of the ancient warship: the red-winged warship and the seven-barred warship.

9. What fish can be caught with garlic?

Garlic can be used to catch crucian carp and silver carp. Other fish are not easily attracted by the smell of garlic or do not like to eat flour bait. However, it is possible that other species of fish may occasionally take the bait.

Whether it is fishing competition or ordinary fishing, bait is always a very important part. In this technical field, it can be divided into two aspects: the selection of bait and the use of bait. Here we are talking about the latter. After you have determined the bait items to be used (it may be a single type or a mixture of multiple baits and additives), the use of bait can be considered from the beginning of mixing the bait.

10. What fish can be caught in Dongjiang River?

Dongjiang Lake is located in Zixing City, Chenzhou City, Hunan Province, with a total area of ​​160 square kilometers, an average water depth of 51 meters, a maximum depth of 157 meters, and a water storage capacity of 8.12 billion cubic meters. Dongjiang Lake is not only rich in tourism resources, but also rated as a 5A scenic spot by the state.

Dongjiang Lake is very rich in fish resources, including rainbow trout, Dongjiang Lake sturgeon, mandarin fish, red carp, triangular bream, tilapia, American spotted catfish, Xiangyun crucian carp, whitebait, sea bass and the four major carps, all of which can be caught in Dongjiang River.