Know a fish every day
Killfish
Fish species description:
Killfish is a common small ornamental fish, also known as big eyes Fish, big-eyed thieves, etc., in terms of biological classification, belong to the collective name of the animal kingdom, the phylum Chordata, the class Teleost, the order Ginkgo, and the family Cyprinidae. There are more than 550 species in 8 subfamilies, 90 genera, and are widely distributed in the world. Found in brackish water, wet water and fresh water all over the world, it not only has a petite and exquisite body and bright and bright colors, but also is favored for its unique breeding method.
Morphological characteristics:
The body of the killifish is spindle-shaped, with a broad and vertically flat head; a large mouth, an extended mandible that is tilted upward; the pectoral fins are very high; the pelvic fins are underdeveloped; The dorsal fin is small, with 6 rays; the anal fin is well developed, with 17 to 19 rays; the caudal fin is truncated; the body length is 25 to 40 mm.
Distribution range:
Killifish are widely distributed in semi-water, salt water and fresh water around the world, including hot springs in desert areas, mostly in South and North America. , in tropical and subtropical swamps and streams in Africa, and in small quantities in Asia and Europe.
Life habits:
1. Environment: Killifish is a warm water fish, the optimal water temperature is 18~26℃, generally no more than 30℃, a few species can withstand high temperatures of 40C, most The species prefers slightly acidic water with a pH value of 5 to 7.5.
2. Food habits: Killifish are omnivorous fish and mainly feed on plankton, aquatic insects, higher plant detritus, etc. Under artificial breeding conditions, they can be fed with fish, insects, and pellet feed.
3. Reproduction: Killifish is an oviparous fish and becomes sexually mature when the body length is more than 25 cm. Female fish can carry 1,500 to 2,500 eggs. The eggs are fertilized outside the body and fertilization takes about 5 to 8 days. Juveniles hatch out.
Identification of males and females:
Generally, female fish are larger, with pelvic fins and anal fins that are light yellow and transparent. During pregnancy, the abdomen is enlarged and soft; the pelvic fins and anal fins of male fish are densely covered with pigment cells. Black, opaque.
Oviposition habits:
A bird with a total length of more than 25 mm is considered sexually mature and has strong fecundity. The egg-laying period is from late May to August. Egg laying takes place in the morning, but eggs can be laid throughout the day when the environment is quiet.
There are two situations of spawning:
(1) The male fish waits at the spawning ground - a place with hornwort and other aquatic plants. When the female fish swims over, the male fish will Swim out to greet them;
(2) Male and female fish swim to the spawning ground in pairs, moving slowly, with most male fish below the female fish.
When laying eggs, the female fish turns around in the aquatic plants and rubs its abdomen, then stops in the grass and begins to lay eggs. At this time, the male fish comes up from the female's belly, parallel to the female, bends its body and falls sideways, approaches the reproductive pore, and begins to ejaculate. The eggs laid by the female fish are piled up around the reproductive pore and appear in lumps. When the female fish swims in the aquatic plants, she uses the filamentous protrusions on the eggs to spread the eggs singly or in blocks on the aquatic plants.
Ornamental value:
Most oviparous killifish have extremely charming body colors, and they are one of the very few freshwater ornamental fish species that can rival marine coral fish. Coupled with its small size and lively and active personality, it is a natural match for aquatic plants in the aquarium.
In addition, most oviparous killifish have wide adaptability to water quality and are easy to raise. They are popular ornamental fish species at home and abroad. The more well-known species include flame medaka, five-line medaka, and black pearl medaka.