What all pond keepers need to know about, fish, koi carp, bubble eyes and gold fishes

This was the only time ever that fish or any other animal were allowed at the Chelsea Flower Show. It was a Japanese garden called The Wonderful World of Koi by Roy Day and Steve Hickling. Yes, with that many koi carp and to maintain that clarity of water, you would need a pretty efficient filter system.

Stocking the pool and suitable fish

Apart from ordinary Goldfish, fish that are suitable for average pools of any size include: Red Comets (Sarasas), Shubunkins, Golden Orfe, Tench and Rudd. These will all happily live with one another. More ornamental cold water Goldfish such as fantails and bubble-eyes, find it difficult to compete with other types particularly in the colder months. It is probably best to 'over winter' them in an aquarium indoors if you want to keep them safe and healthy.

Although they are coldwater-hardy these Bubble Eyes are best kept in a tank indoors because they just could not compete with the fray of pond life.

Although happy in an outdoor pool in winter, the various forms of Fantails, being slower movers than many pond fish, would find it difficult to compete in winter. An indoor tank or pool would be recommended.

All the above fish are quite content to share their lives with Koi Carp. However serious keepers of Koi Carp need to think in terms of a minimum depth of 3ft - preferably 5 to 6ft - with a proportionately large width and length.

Koi keepers very often have to think in terms of no plants or at least have them protected from the vandalism of the fish. Therefore because of the lack of the biological cycle in which plants form an essential link, and also because of the rapid metabolism of these potentially very large fish, a sophisticated filter system is essential in keeping Koi. They are not fish of extremely cold water and find our winters stressful to say the least. When fish are stressed, then they are open to disease and parasites, and since Koi are such expensive fish, the only way to keep them with confidence is to employ all the quirks of pool design and filter technology at your disposal.

There are always exceptions to the rule and here in one of my first ponds, this one in Bath, koi do live in a tolerable harmony with plants. There is no filter in this pool although there is along stream. Perhaps it is because they were introduced to this environment very early on in their lives. But not the scum on the surface; I would argue that the plants are not doing as well as they might have done without the fish, but I am sure the fish really appreciate the plants.