Buying & Stocking Fish
Try to provide adaquate quarantine facilities before you purchase new koi, a successful quarantine set up should be a scaled down version of your own pond, with many of the same principles applied. Very often indoor set-up's are used, with some form of heating included. Some enthusiast's make customised fish houses complete with all kinds of paraphernalia.
Quarantine for at least 8 weeks preferably longer if you can, before adding new koi to your pond. Ensure that all parameters are the same in your pond as your quarantine, then dd your fish to your pond. Never buy more koi than you can adequately cater for in your quarantine facility. Stock you pond slowly, never overstock, allow for growth and development.
When purchasing a koi study the fish looking for normal movement and swimming action. In dealer's ponds the competition for food is intense. If at feeding time your potential purchase is feeding along with the other fish this is a good start, so you may ask the dealer/seller to feed them and watch for a reaction from the koi that is. Healthy koi swim with fins erect, never hide away or hang listless in the water, they dont hang around aeration areas for long periods of time.... unless they have found some pellets that their felow pond mates have missed.
Koi should have no reddening or any other unatural skin condition, such as if they have been dusted with talcum powder, no cotton wool type fungus should be present, neither should split fins, raised scales, ulcers or waxy white nodule type skin and fin spots, commonly known as carp pox.
Fish that are unaturally thin or fat should be avoided. Ask the dealer /seller to show you the fish's gills they should be a healthy red and intact, not muddy, grey or conjested in mucous. Watch for a steady gill movement, the gill covers should never stand proud of the gill plates.
If youy are unsure of your own judgement always be prepared to ask an experienced koi keeper to help you decide in your choice, but remember the final responsibility will be yours alone.
Have your potential purchase bowled for viewing, preferably under natural daylight, find out as much as possible the history of the koio, including breeder, approximate age, sex if possible, any tratments carried out, and full details of the water qualities it's being kept in.
Gradual adjustment to your own quarantine system water parameters is essential, ensure you know them, and take an hour or so to settle the fish into its new surroundings after purchase. discard old water and plastic bag after you have released your koi.
Trust your own instinct and never buy fish that are suspect, and never put suspect fish into your collection. In honesty most of us have risked it and regretted it!!