Conditions of KOI carp breeding.
Basic care of KOI carp during the year is mainly in checking the hydrochemical properties of water regularly and in supplementary feeding the fish. Their density should be 80 cm of length of the fish per every 1 m3. Natural food for common carp – plankton and benthos (fauna of the water coumn and fauna of the bottom) – is not present in the pond in sufficient amount and thus it is necessary to give supplemental feed to the fish regularly. Feeds should be with balanced nutrients and they can be sorted into several basic categories – for breeding all the year round, for advanced growth, for winter period and for the transition period. Feeds are mostly produced as floating pellets to give us a view of the fish which have to approach to the water surface to feed themselves, as well as to give us an information how much feed the fish accept. As a rule, we shall give the fish so much feed they can consume in 5 minutes. It is better to feed the fish more times a day with smaller amount of feed than vice versa. We do not feed overnight. Doses of feed shall be lowered when the temperature drops below 15°C. We do not feed the fish in winter as well. Fish placed into a controlled environment during winter are to be given slight supplemental feeding.
Clear and sufficiently oxygenated water is very important for KOI carp breeding. It regards the fish health status, as well as that the fish are well visible. Water quality (hydrochemical properties) must be regularly checked. We have to focus namely on pH level, amount of oxygen dissolved in water, contents of nitrates, nitrites, eventually on free ammonia concentration. As this concerns specialized services, the best solution is to address the firm which supplied the filtrating unit or firms performing water analyses in the region. For example, the pH level should be 7 (with possible range 6 – 8.5) and the amount of oxygen dissolved in water should not drop below 5 mg per litre (the optimum is 8 – 9 mg per litre). Values should not fluctuate dramatically in any case.