Before you decide to introduce fish into a pond consider that fish like all animals will require some of your time and attention.
Whilst everyone realises they require feeding, few consider the cleaning.
Fish and fish food foul the water. Some provision must be made to rectify this problem either by filtration and some water changing or without filtration by more frequent water changes.
To maintain fish health and prevent fish losses the pond water will require periodic testing to regulate its condition. All of which involves a little effort on your part. But at least they do not have to be taken for walks, do not make a noise and can be left without concern for two or three weeks to their own devices when you are away on holiday.
Decline gracefully anyone who offer to feed your fish.
Always purchase fish from a reputable supplier, stand a while and look at them, see that they are alert, free swimming with all fins raised. Reject any fish that is damaged, has wounds on the body, if the fins have blood streaks in them or are frayed, and if the fish is lethargic or is swimming with closed fins.
Look for a fish that is both alert active and has a good swimming action.
An excellent test of a fish's health is to net the fish and turn it on its side; if the eye is looking straight up i.e. level with its body, reject it. In a healthy fish the eye should be raised above the body along the upper edge.
The most common fish kept in ponds are Goldfish and their close relations Koi.
One should refrain from introducing the more fancy varieties of Goldfish into ponds, as these tend not to survive over winter, especially Twintails.
As the name implies these fish have been bred with two tails and are best suited for indoor aquarium display.
The varieties of Goldfish best suited for ponds are the Singletails, these are the 'fish-looking' fishes, such varieties as the Common Goldfish, the Comet and the Shubunkin.
Common Goldfish and Comets are available in red, orange and yellow body colours, Shubunkins are multi coloured with a mother of pearl appearance.
Pond Goldfish will grow to around 200mm/8" depending on the size of pond as they tend to adapt their size to the environment.
A Rule of Thumb when stocking is to allow 1cm of fish body length for every 60cm2 of pond surface. However when first introducing fish start by allowing 3cm of fish for every 60cm2 of pond surface and if all goes well after a month or so you can introduce two or three more.
But please remember the fish will grow so this must be allowed for.
Except for the rare long-finned variety, Koi (Japanese for Carp) have retained their basic Carp body shape.
Their attraction lies in the many colour varieties available.
Mixing base colours of Red, Yellow, Black and White in various combinations gives a very wide choice; add skin and scale variations, together with the varying amounts of reflective material below the scales, and one has a huge choice.
Koi can grow up to 900mm in length as they do not seem to be restricted to their environment to the degree that Goldfish seem to be.
Although the same criteria applies when stocking with Koi as with Goldfish, their eventual size must be borne in mind when stocking a pond with Koi - they will grow very much larger!
OTHER POND FISH
With the exception of Grayling, Trout, Miller's Thumb, Stone Loach and Minnows, given the right conditions most Native Fishes can be kept in ponds.
However it is best to keep to those species that are found in natural ponds or small lakes - Roach, Rudd, Tench etc.
Some are protected and require a licence to own, for instance the Barbel and the European Bitterling.
The drawback with keeping native fish is that their coloration is designed for protection against birds like Herons and this makes them hard to see in a pond.
However there are available cultivated Golden varieties of both the Rudd and Tench and, although not a native of Britain, the Golden Orfe a coloured variety of the native European Orfe (Idus idus).
All native fish will grow to their normal size, with the coloured varieties being slightly smaller.
With the recent introduction of government legislation, the keeping of non-native fishes in the pond has become more difficult as these species require a licence to be kept by both the dealer to stock them, and the pondkeeper to own them.
This rules out many of the popular North American fishes for most people.
© FBAS 2004 RCM/RDE Pond Care Sheet 6 1/1