Pond fish: breeding
Thus, the spawning period is defined more clearly than most tropical species, for which the importance is not so much the temperature, the amount of rainfall.
You can determine the start time of spawning, regularly measuring the temperature of the water in the pond, because the spawning usually begins at a temperature of about 20°C. At this temperature the eggs develop normally. Plus or minus 5 °C, and the fry will be deformed, because things will develop too quickly or too slowly.
Physical changes in the fish also indicate the approach of spawning. For example, the males of the family Cyprinidae appear white swellings, called tubercles. Fish such as Orfe, Rudd, goldfish and koi, the tubercles appearing on the Gill covers and pectoral fins, while Cipriani – along the scalp.
Some fishes, such as sticklebacks, coloring of the male becomes brighter, attracting mates and scaring off rivals. Females of all cold-water species become fuller males.
Because before spawning inflated from the calves. In addition, during this period in the pond reigns an extraordinary excitement: the males relentlessly chase the females, often colliding with them, or poking them in the nose.
Coldwater pond fish do not form long-term pairs: any partnership between a male and a female temporarily. Fertilization occurs outside the body: egg and spermatozoides in the water at the same time. The majority of fish species, including goldfish and koi, dropped the eggs. They randomly release their adhesive eggs, which either sink to the bottom or stick to the leaves and stems of aquatic plants. Fertilized only a small percentage of eggs, and in order to compensate for fish spawn them in huge quantities up to 40,000 per spawning in the case of koi.
After spawning, most fish don’t pay any attention to the eggs or the fry, but some species show some concern for the survival of offspring. Black tolstokorov, for example, spawns in caves and under stone ledges to hide it from predators, and male stickleback watching as for the eggs and newborn fry.