The carp genus, belonging to the family Cyprinidae, represented by two species — silver and gold, or common carp.
The Golden or common carp is as carp and common carp dorsal fin long, hard spiny rays in dorsal and anal fins, but is distinguished by the absence of antennae and a single-row pharyngeal teeth. The back is dark brown, while the sides are Golden with a copper tint. Pectoral and abdominal fins reddish. It lives in Central and Eastern Europe, and in Siberia in swampy, overgrown ponds, in rivers is rare. Likes silt. For the winter carp buried in silt and hibernate even when shallow waters freeze to the bottom. They are able to burrow in the mud at a depth of 70 cm and this allows them to survive the dry summer, when shallow body of water completely dries up. It sustains the concentration of oxygen dissolved in water to 0.5 mg/l, lowering the pH to 4.5. The Golden carp is one of the most hardy species of fish and in some waters is the only representative of the fish population. Can reach masses up to 3 kg, and I individual weighing about a pound are a valuable trophy.
With all the advantages of common carp, unfortunately, it is slow-growing. Although in the southern regions the first year of growing under favorable conditions may reach a weight of 20 to 50 g, in the second year — 200 and even 300 g. In the middle zone two-year old Golden carp in prodajne exceed weight 100 — 150 g. Females are larger than males. Reach sexual maturity at age 3 to 4 years. Spawning takes place at a temperature of 14 °C. the Fecundity of females up to 300 thousand eggs. Caviar adhesive, is attached to underwater vegetation at depths of 0.5 — 0.6 m. Approximately two weeks after the first spawning, watching re-spawning. Spawning is gregarious, noisy. Fertilized eggs develop 2 to 4 days depending on temperature. Biology of the Golden carp is similar to silver. However, the latter has peculiarities in reproduction.
Silver crucian carp differs from the silver gold color of the abdomen and sides. Inhabits Europe, Siberia, the far East, in China. Now imported to North America, India and other regions. Unlike Golden carp can be encountered in large rivers, where it prefers places with no fast currents. Grows faster than ordinary carp. Two-year old reach the masses 300 — 400 g in the South and 150 — 200 g in the middle lane. They can reach a weight of over 1 kg. Feeds on zooplankton, phytoplankton, benthic animals and detritus — dead remains of plants and animals.
In the communities of silver carp observed an unusual sex ratio. Most often the females are much larger, and in some waters the males are absent. However, the carp reproduce in the offspring appear again some females. This method of reproduction is called gynogenesis or translated into Russian language — the birth of females. The fact that the eggs of crucian carp already has a double set of chromosomes and it does not need to merge their core with the nucleus of a spermatozoon. However, in order to stimulate the development of eggs requires an entry of any sperm, which subsequently resolves. Female same-sex communities such breed involving males of other species of fish of the carp family, which spawn at the same time silver carp. It can be male Golden carp, tench, carp and other fish. It is also interesting that the deterioration of the conditions of existence in Karasevich communities may again appear males. Females grow faster than males, therefore in ponds growing gay community, only females. Feature of goldfish is its amazing ability to change appearance under the influence of various conditions. It was used in the derivation of a goldfish — direct descendant of silver carp. First goldfish was developed in China about a thousand years ago.
Now goldfish are one of the most popular aquarium and ornamental pond fish farming. There are many breeds that are not much like the ancestor of the goldfish, including comet, veiltail, livingonlove, telescopes and many others. Interestingly, live goldfish with proper care is quite long — up to 40 years. In stagnant waters and ponds slow the gold and silver carp can be grown in monoculture, that is, without other kinds of fish. Planting density — 1 — 2 yearling 1 m. In this case, the feeding in Central Russia by the autumn they reach the weight of 100 — 200 g depending on the species. As an additional fish carp are grown at a density of about 1000 properties on 1 ha. is considered a Commodity carp weighing about 300 g. in this case, the meat quality is not inferior to the common carp the same sample.