Morphological characteristics: Sunfish with black spines are often found at the same time as Sunfish with white spines. Although Sunfish with black spines likes larger and clearer water than Sunfish with white spines can tolerate, both of them are widely distributed in ponds, lakes and rivers. The average weight is between 340 and 680 grams, and the maximum weight can reach 2.27 kilograms.

Origin: Eastern North America from southern Canada to the Gulf of Mexico, and widely introduced to other places.

Blue gill sunfish

Blue gill sunfish is a species of the genus Cynanchum in Perciformes, and another excellent freshwater species introduced from the United States. The blue-gill sunfish is similar to some fishes in the family Sparidae, oval in shape, with a flat back and a high height. The individual is small, generally 80-150g/tail, with 10 gray-black horizontal stripes. The body color is metallic purple, green and yellow, which is very beautiful. In the breeding season, the male fish is more bright and dazzling. The blue gill sunfish has a wide temperature adaptability, and can naturally spend the winter without taking heat preservation measures in winter. The feeding habit of this fish is omnivorous flat meat, but it is not a fierce fish. It is gentle, resistant to low dissolved oxygen, fat and water, and has strong disease resistance. The fish is sweet and smooth, with excellent taste, which is very popular in the market.

March ~10 every year is the breeding season of blue gill sunfish. At this time, the male fish body color is particularly dazzling and very beautiful. Generally, females with a length of 15 cm can lay 65,000 eggs for many times. The fish has wide temperature adaptability and can normally feed and grow at low water temperature (12℃).

The feeding habits of blue gill sunfish are mainly animal. Under the condition of artificial feeding, feeding artificial compound pellet feed can completely meet its growth needs, and the protein content of feed is 32 ~ 362/0. The fish has strong adaptability and can grow in both large and small water bodies. Its culture method is single intensive culture in Caizhuan pond, the pond area is 3 ~ 5 mu, the water depth is1.5 ~ 2 m, and 3 ~ 4 cm/fish fry1000 ~12000 per mu are stocked. Feeding palatable granular materials, the daily dosage accounts for about 100/0 of the fish's weight, and when it grows to about 100g/tail, the daily dosage accounts for 70/0 of the fish's weight, depending on the weather change and food intake. In the process of culture, the fish rarely gets sick, but we should still pay attention to the prevention and treatment of fish diseases, and the prevention and treatment methods are similar to those of other freshwater fish.

The individual is small, but the meat is extremely delicious, which is incomparable to many famous fish.

Set ornamental, hanging hook, edible as a whole, is a new breed. Experiments show that phytoplankton, tilapia fry, snail and turnip are disliked or hard to get by green sunfish (for example, tilapia fry may be difficult to catch); Cladocera, copepod, earthworm and chironomid larvae are preferred or easily obtained by green sunfish; Cladocera, earthworm and chironomid larvae are the favorite foods. Dissolved oxygen requires that when the dissolved oxygen drops to 0.5 mg/L, the fish will float and stop eating feed. Dissolved oxygen10 mg/l or more, with bait-taking behavior; The dissolved oxygen is more than 2.5 mg/L, and the feeding intensity is relatively high. The highest record is that the feed accounts for 5.6% of the total weight of fish.

Water temperature requirements According to the wintering performance of green sunfish in cement ponds from February to February, 2000, it is proved that it has strong low temperature resistance (according to reports, its minimum critical temperature is 3℃), so it is unnecessary to heat up for protection. In the meantime, puffed pellet feed is fed daily. The author observed that when the water temperature was 12℃, the green sunfish still had feeding behavior.

Comprehensive evaluation The green sunfish is a newly introduced breed in China, and its biological characteristics are currently being studied. The author thinks that green sunfish belongs to mild carnivorous fish according to nutritional types. From the analysis of its food composition, the main foods of green sunfish are cladocera, aquatic annelids and aquatic insects larvae; The secondary food is copepods; Snails and small fish are accidental foods; For green sunfish, artificial compound feed should be classified as "alternative food".

The open bait of green sunfish is phytoplankton, rotifer and small cladocera. This characteristic provides convenient conditions for the development of green sunfish production. It is expected that the method of cultivating fry in conventional pond can solve the bait problem of fry.

The feeding habits of the green sunfish are similar to those of the blue-gill sunfish. The larvae of the blue-gill sunfish were fed with cladocera and copepods at the initial stage, but the results of this study show that phytoplankton is one of the open feeds of the green sunfish, which is somewhat different and is also a favorable factor for raising the green sunfish. The cultivation of green sunfish will depend on the application of artificial compound feed, and the nutritional requirement of green sunfish is the basis for the future study of compound feed, which needs further study.