When things go wrong with koi
Having a garden pond stocked with koi places a certain responsibility on the owner. This responsibility increases as the stocking density in the pond increases. If there were only three or four smallish fish in your typical garden pond, very little attention will normally be needed from the owner. The koi will even survive an extended period without you giving them any food because the pond will provide them with natural food. But as you put more fish into the pond and the larger the fish become, the more they will be dependant on you for survival.
A large collection of beautiful koi will be fully dependant on their owner for their basic needs. You will need to feed them on a balanced diet of fresh koi food. You will need to fit pumps and filters to the pond to ensure that the their waste is removed and good water quality is maintained. You will need to aerate and circulate the water by some means in order for the koi and all other life in the pond to breath. Failing this, things are sure to go wrong in the pond.
Parasite are enemy number one. When fish are under stress due to overcrowding and poor water quality, they become easy pray to parasites. But even in the best kept ponds parasites can from time to time become a problem. There are a few early warning signs. Your koi may scrape or ‘flick’ their bodies against objects in the pond. They may swim slowly with one or both pectoral fins clasped against the body. Sometimes they hide in the quietest corners of the pond where the water flow is at a minimum. Watch for fish ‘sitting’ at the bottom or hanging near the surface at a angle and breathing heavily.
Pond keepers should make a habit of observing their koi with care while feeding them. Those that do not come eagerly for food, could have a problem. If a fish do not show an interest in food for two or three days in row, there must be something wrong and the pond keeper must resort to treatment.
It is important to give the right treatment. The novice should get advice before attempting to medicate his pond with something off the shelf. Talk to your koi dealer or local S A Koi Keepers Society to establish who can best diagnose your problem. Take a sample of your pond water in a jar for analysis and if possible, a sick fish for microscopic diagnosis. Treatment can be swift and quick if the correct medication is used and will prevent secondary complications.
Note: To transport your sick fish place it in a clean plastic bag (dustbin bag will do) in a bucket or cooler box and fill one third with pond water. Put the fish inside the bag and close the bag with a rubber band or knot in such a way that air is trapped inside. If the bucket is kept in a cool place, the fish can quite easily travel for an hour or more like that.
There are many books on the market or in the library that can enlighten the novice about all the fascinating aspect of koi keeping. Information is also available on the Internet in the news group rec.ponds.
Written for Animal Talk magazine
Servaas de Kock & Ronnie Watt