Extended data
There are only 1 species in the world, namely, Menemacata (Bloch &: Schneider, 180 1). It mainly lives in deep water and sometimes swims to the coastal waters for food. It is a carnivorous fish that feeds on zooplankton or benthos. I like to chase things that shine, and I have phototaxis. Distributed in tropical and subtropical waters of Indo-western Pacific.
The blade is slightly triangular, high and extremely flat like a knife, so it is called "leather knife". The back edge is almost straight, and the belly edge is round and sharp. Small head and high pillow. The mouth is small, almost vertical, and the front jaw can be extended. There are villous tooth bands in the upper and lower jaws; Palatal bone has no teeth. The branchial fissure is large, and the branchial quilt frame is 7;
The branchial membrane is not connected and separated from the throat isthmus. The tiny scales covered on the body surface make the skin smooth and difficult to see with the naked eye. The lateral edge is incomplete, parallel to the dorsal edge, and the posterior end only extends below the end of the dorsal fin base.
The dorsal fin is single, the base is very long, the degeneration of the hard spines in front is not obvious, and the soft strips in front are slightly longer; The anal fin is short and the fin tip is exposed; The pectoral fin is wide and short; The ventral fin is in the chest position and has I+5 fins. The fin is slender in childhood, and only the first fin protrudes in adulthood; Tail fin fork
Tall and particularly flat, thin and tall, shaped like glasses. General body length 10 ~ 20cm, weight 75 ~ 200g g. The body radiates nearly triangular, the back is straight, the abdomen is particularly curved, and the abdominal edge is thin and sharp. The outline of the abdomen is curved, the abdomen edge is convex and thin, and the back side is slightly curved, hence the name.
Scales are so small that you can touch them without seeing them. The mouth is small, almost vertical, elastic and inclined upward like a tube. The anal fin is low and the base is long. Most adult fish are buried under the skin. The tail handle is short and the side is flat. The caudal fin is deeply bifurcated, and the upper and lower leaves are equal in length. The ventral fins are small, but two of them are very long. The upper part of the body is dark blue, the lower part is silvery white, and the pectoral fin is pale yellow.
There are 2 ~ 3 rows of black circular spots smaller than the eye diameter on the upper and lower sides of the lateral line. The end of the maxilla only extends below the eyes. There are tiny scales on the body, which are not easy to see with the naked eye; Small head and high pillow; The mouth crack is small, nearly vertical, elastic and inclined upward like a tube; Branchial fissure is large, branchial membranes are not connected with each other, and there is no isthmus. The head, pectoral fin and caudal fin are all in the upper part of the body.
The dorsal fin is single, without spines, and the anterior fin is long without bifurcation; There are no hard spines in the gluteal fin, and the soft strips are wrapped under the skin, only the outer ends are exposed; The ventral fin is long and located at the ventral edge, and the first fin of adult fish extends into filiform shape; The caudal fin is deeply forked. The body is silvery white and the back is blue, with many blue spots scattered on it. Fins are very light in color.
Body length105-217mm. The body length is 1- 1.6 times the body height and 3-3.6 times the head length. The body is diamond-shaped, extremely flat, with a protruding abdomen, a blade-like abdomen edge, a small head, a flat side and a high occipital ridge. The head length is 2.4-2.6 times that of the kiss and 3.4-4. 1 times that of the eye diameter. Eyes are the same size, located in the middle of the head.
The mouth is small and the crack is almost vertical. There is fluff on both jaws. Palatal bone has no teeth. Branchial foramen is large. The number of gill rakes on the first branchial arch is 7-8+23-27. Scales are very small and fall off easily. There are two lateral branches: one dorsal branch bends from the back corner of gill cover to the front of the starting point of dorsal fin, and the other is parallel to the trailing edge and extends above the caudal stalk.
Dorsal fin spines are obvious in young fish, but only four spines remain in adult fish and are buried under the skin. The gluteal fin has two stings in childhood and degenerates in adulthood. Most of the gluteal fin strips are buried under the skin, and only the ends are exposed. The spine of the ventral fin is short, and the first fin of the ventral fin is particularly long when it becomes a fish. Tail fin bifurcation. The back is blue-brown, and the abdomen is silvery white. There are round or oval black spots on the side.
Real estate season
Origin: distributed in tropical and subtropical waters of India and the western Pacific. China is made in the South China Sea and the East China Sea of China, with more production in the South China Sea.
Habitat ecology: mainly inhabit deep-water areas, sometimes swim to coastal waters for food, and even be found in estuaries. It is a carnivorous fish that feeds on zooplankton or benthos. I like to chase things that shine, and I have phototaxis.
Season: The fishing season in Hainan and Guangdong coastal areas is from April to July.
economic value
Edible, less meat, crisp meat, poor taste and no nutritional value. Coastal fixed nets can be used for fishing. In addition, towel nets and trawls are often used for fishing in large quantities. It can be used as live bait for offshore longline fishing, and can also be made into fish meal or cat food.
Every100g of fresh edible part contains 76.3g of water, 7.3g of fat, 2 10/0g of calcium, 50mg of phosphorus, 5.6mg of iron, 0.02mg of vitamin B, 0.07mg of vitamin B2 and 3mg of nicotinic acid.
References:
Eyeglasses fish. Baidu baike