There was a time when many ponds were referred to, especially by monks, as ‘carp-pools’. For adjacent to many a monastery lay a pool well stocked with carp. Those fish often grew to a prodigious size, and when a meal was required, a monk or retainer simply netted a basket of fish. Refrigeration and improved transport put an end to the practice. But carp are still to be found in public and private lakes and ponds. The native Asian Carp, Cyprinus carpio, was introduced to Europe a long time ago. It averages about 30 to 40 cm. In length, but specimens 100 cm. Long and 20 kilos in weight are not unknown. The Asian Carp is easily distinguished from the European Crucian Carp, Carassius carassuis, by having two barbels on each side of its upper jaw. Carp are extremely tame and will often cruise to the surface well within reach. I sometimes wonder how many of them may have provided a meal for some hungry poacher or tramp. There is no reason why one should not keep these friendly creatures in a largish pond except that their dark colour makes them rather inconspicuous. And they revel in rooting in the bottom of the pond and tearing up aquatic plants. So far as carp are concerned, the obvious choice for the ornamental pond is from the numerous varieties of goldfish (Carassius auratus). There are over one hundred recognized types — all relatives of the humble carp.

Regardless of the varieties you choose, do select healthy fish. There is no difficulty in identifying them. A goldfish in the peak of condition will have an erect dorsal fin and his movement will be definite or vivacious. A sick fish will lie on the bottom, be motionless or almost so; and if he is not capable of swimming upright or keels over at all, then do not buy him. Presumably, you will transport your fish home in a polythene bag with water taken from the tank in the shop. This water may well be at quite a different temperature to the water in your pond. Fish are cold-blooded creatures which means they adapt their blood temperature to that of the surrounding water. They can survive in extremes of temperature, but they cannot adapt instantly from one extreme to another. So, rather than release your fish immediately into the pond, allow the polythene bag, with the neck open, to rest in the pond until the water in the bag is within a few degrees of the water in the pond. Then simply tip the bag over and release the fish. He should then dart off to hide in a clump of weed, under a rock, or if he is a larger specimen, he may begin exploring the pond immediately. And it is best not to introduce fish to a new pond until the underwater plants are growing well. This way one knows that the water is in fit condition for livestock.

The utter stillness of aquatic plants, especially the water-lily, in a way begs the constant motion of fish. If you have had the opportunity to become used to both in one pond, then you will almost certainly feel something is missing in a pond which has only one of these elements. And the relationship is not solely an aesthetic one. Fish may be chosen primarily for their ornamental value but they are also useful scavengers, protecting lilies from the onslaught of insects, among other creatures. They are worth including in a pond for this reason alone. And no fish is more beautiful nor more effective a scavenger than the Golden Orfe (Idus idus), which is also available in a silver form. Long, slim fish that quickly grow up to 30 cm. And more, they tend to move in shoals especially when small and can whip and dart through the water at great speed. More important, they spend much of their time at the surface, will readily take floating food including insects, and are on view frequently. Their characteristic flight through the water makes for a very satisfying contrast to the more languid, peaceful movements of the common goldfish which are, however, even more tame. Indeed it is not unusual for goldfish to become so tame that they will feed directly from the hand. Once this practice is established, as soon as you appear the fish will congregate at your feet. So too will Shubunkins or Calicoes which are varieties of goldfish, but which come in multicolours of red, black, brown, purple, white and most highly prized — and priced — of all, blue. They appear almost scale-less on account of the fact that their scales lack pigmentation. Shubunkins are also available in single colours and are very conspicuous fish. The sleek Hi Goi Carp are also available in a variety of colours. They are clearly scaled and have two pairs of barbels.

Breeding grotesque and outlandish forms of goldfish has been brought to a fine art in Japan and America. Veiltails or Fantails have squat, fat bodies with long flowing tails usually in three sections and often as long as the head and the body put together, indeed sometimes longer. The Black Moor has, in addition to this kind of body and finnage, great bulbous, telescopic eyes. So highly developed has the finnage of these fish become that it is almost inoperative. Veiltails and Black Moors can only strut through the water like so many fat duchesses. This can be a problem if the fish is dependent upon food you throw into the water.

Golden Orfe and the common goldfish easily outstrip them in speed, so special provision has to be made for them to be certain they do not starve to death. In a well-established pool with plenty of underwater plants all fish should do well enough grubbing for midge larvae, algae and other natural foods. Fantails and Black Moors are more susceptible to ailments than ordinary goldfish. In particular the air bladder, situated in the centre of their squat bodies, which controls their sense of balance, often gives rise to problems. If you are attracted by their long, flowing tails, but feel the Fantail is too ungainly or troublesome, then a compromise is possible in the Comet Goldfish. Their conspicuous tail fins are about a third of the length of their bodies, but short enough to be functional. They are very agile fish. All sorts of combinations of fancy characteristics have been bred into goldfish apart from elongated finnage. There is the Bubble Eye, and the Celestial Goldfish whose eyes are situated on top of its head. But to my mind the most grotesque of all is the Lionhead which has large warts on its head not unlike the seeds of corn-on-the-cob. The more perfect the symmetry of the finnage of these goldfish, or the more highly developed their grotesqueries, the more expensive they come. In a pond, as opposed to an aquarium, where one is normally looking down at the fish from some distance, the finer points of symmetry are not apparent and one is as well off buying the cheaper, less perfectly shaped specimens. Symmetry is no indication whatever of the health of a fish, although it can be said that the more squat the body the more vulnerable is the fish to ailments.

Golden Orfe are not likely to breed in the average pond, but goldfish will breed readily during warm spring conditions. It is possible to buy goldfish in breeding pairs at extra cost. But this is hardly necessary as any five or six fish are almost certain to contain both sexes. Come the warm weather and the females or hen fish who are ready for spawning will develop fat, rotund bellies, while the males, or cock fish, who are ready for mating very often develop a pattern of small dots on their gill plates. A temperature of 15°-18°C. Is favourable to spawning.

The mating ritual consists of males frantically chasing a female round the pond, chivying and nudging her flanks encouraging her to spawn. Often this ritual goes on for hours at a time. Sometimes the female is cornered and almost forced out of the water. Occasionally her flanks can become torn from friction with rocks or the walls of the pond. This can lead to fungal infection, especially if the female is exhausted by so much attention. That, however, is the way with nature. In time the eggs are deposited usually on dense weed in shallow water and the male fertilizes them.

Several spawn-ings may occur over a period of ten days. Depending upon the temperature the eggs will hatch in about three to five days. The fry are tiny, no larger than the head of a pin. It may be several months or even the following season before you spot them: thin, translucent initially and only a few millimetres in length. Fish are notorious cannibals and it is an advantage to have a shallow area in your pond in which the young can take refuge — in theory, if not always in practice, the larger fish will stick to the deeper areas. As they mature, some of the fry will take on the colour or mixed shades of their parents; others, unfortunately, will revert to the plain blackish-brown of their ancestors. Some may, in time, lose this dull colour in favour of red or yellow, but for a certain number black or olive brown will be their permanent colour. In commercial breeding, selection procedures are adopted and bright red hues are encouraged by the use of chemicals and high-temperature tanks. So far as pond fish are concerned, one has to rely on natural sunshine. But this does not mean preventing the fish from having adequate shelter in terms of rocks and weeds, which are essential to their well being. In an aquarium, artificial lighting may encourage fish to change colour, always provided, of course, that the individual fish has that potential. Again it is important to ensure that the fish have adequate cover should they want to use it.

Goldfish rarely suffer from underfeeding but are vulnerable to being fed too much too often. In winter, fish in an outdoor pool hibernate, hidden among the weeds, emerging only during warm, sunny spells. They require no feeding at all during this time and any food they look for can easily be found amongst the weeds. In summer, in addition to fish pellets and other patent foods, fish are grateful for an occasional diet of chopped worms, if you can bear to chop them, Daphnia and a portion of a hard-boiled egg that has been very thoroughly chopped up or minced. But whatever you feed your fish, never give them more than they can consume within about fifteen minutes. If food is left lying around, not only will it discolour and possibly pollute the pond (boiled egg is a particular danger), but it is a sure indication that the fish are being overfed.

In a well-planted pool, the base of which is almost covered with oxygenators, feeding is hardly necessary at all. So you can limit the expense of buying fish food to those occasions when you want to bring the fish up to the surface and close to view, and to tame them. Feeding in spring may encourage your fish to breed; while in autumn it should build up their strength for hibernation. Of particular value to fish fry are the minute organisms known as infusoria associated with decaying vegetable matter. Infusoria can be prepared by taking a little water from the pond in a jar and suspending in it a bruised and rotting lettuce leaf. Spinach leaves, lentils, the dead leaves of water plants and even a banana skin will serve the same purpose. Best results are likely to be obtained if the water temperature is around 22°C. Or above. After a few days you can judge whether infusorians are present by holding the container up to the light. The water should appear as if filled with a greyish-white dust. These are the infusorians. Simply tip the contents of the container into the pool, preferably at roughly the same temperature as the pool water, to prevent killing the culture. To have seen the Koi Carp is to have seen the most magnificent of all pond fish. Unlike Shubunkins, their scales are very obvious and pronounced and their colours are even more striking, especially the golden form. There is no more brightly coloured ornamental fish available. The golden form is truly the colour of gold, not merely a shade of yellow. And Koi are not simply tame. They are fearless. Dip your fingers in the water and immediately you can expect your hand to be surrounded by Koi, all clamouring and jockeying for position in the expectation of tit-bits. They grow to great sizes, and a pond containing five or ten Koi, each weighing upwards of two kilos, is an unrivalled sight. You could, however, buy a three-piece suit for the price of one such fish, and still have change in your pocket. Better to begin with small fish and feed them up. But that is one of the drawbacks of these beautiful fish. They have large appetites and require a substantial diet that might include Tubifex, Daphnia, pelleted food and small earthworms. They are by nature bottom feeders and have the habit of churning up the soil in baskets or on the bottom of the pool and uprooting aquatic plants. It has to be said that water-lilies and Koi are not wholly compatible, unless your pond is a large one. And they like deep, well-oxygenated water. A waterfall would be an obvious advantage. Green and Golden Tench (Tinea tinea) will live in harmony with goldfish and are often recommended for ponds on account of the fact that they are scavenger fish, eating detritus and grubbing around in the bottom of the pool. The fact that they can survive in water with a low oxygen content makes them easy to keep. But being bottom feeders they are rarely seen in a pond which has an adequate planting of weeds; and their value in mopping up dead snails and keeping the pond clean is probably over-estimated. Similarly, the little Bitterling (Rhodeus amarus), 8 or 9 cm. Long, and the Gudgeon (Gohio gobiol are not likely to be seen or noticed. On the other hand a small shoal of Minnow (Phoxinus phoxinus) is an attractive feature. True, their colour is nondescript, but their activities, flitting around, suddenly seen in one space only to disappear into a clump of weeds and reappear somewhere else, make them worth keeping. Apparently their habit of scattering — as opposed to staying together — in the face of danger, is a tactic for survival. It is believed that a predator is unable to concentrate his attention on one particular minnow when a shoal scatters in all directions.

And the Stickleback (Gasterosleus aculeatus) is certainly worth including, not only for its subtle colouring of red and blue lines along the flank, but also for its characteristic movement and above all for its unusual life-style. The stickleback always appears as a very self-possessed little fish, thrusting itself through the water at great speed and then pulling up sharply to remain motionless until it gets it into its head to take off again, and again pulling up dead as if attached to some miniature and invisible braking system. At mating time, usually from early spring until midsummer, the female loses her greeny black colour for a shade of yellow; and the male’s flank takes on a strong red hue, his back a bright green and his eyes become electric blue. He then sets about collecting small pieces of vegetation which he glues together in some nook, and this serves as a nest. The glue is secreted from the kidneys. An elaborate courtship follows during which the female or females are enticed into his parlour to lay their eggs. Once the nest is full of eggs, the female stickleback has no further duties. The male takes charge of the eggs, fertilizes them of course, aerates the water in their vicinity by vibrating his fins, and protects them and the hatched fry until they are old enough to fend for themselves. Any young stickleback who tries to leave the nest before father approves is taken in father’s mouth and thrust back into the nest. Sticklebacks are not, contrary to what is sometimes said, a danger to other species of fish. They keep their aggression for defending their territory against other sticklebacks. The same is certainly not the case with the ferocious catfish (members of the genus Corydoras are the ones commonly kept in aquariums) who will eat all before it. And under no circumstances should the Brown Trout (Salmo trutta), the Common Perch (Perca fluviatilis) or the Pike (Esox lucius) be introduced into ponds which contain goldfish.

About introducing such predatory fish with goldfish there is no debate at all. Trout, perch and pike will devour the goldfish. About introducing snails and mussels, opinion is somewhat divided. If your interest in a pond embraces the creatures it can support as much as the plants, then snails in their various shapes and colours, their behaviour and egg capsules, will undoubtedly add to that interest. Snails are valuable in that they eat decaying vegetable matter and perhaps serve a purpose in keeping the pond free of pollution. Not all of them, however, limit themselves to decaying matter. The Great Pond Snail, Limnaea slagnalis, is very partial to Frogbit, oxygenating plants and the leaves of water-lilies, especially the smaller plants. This snail can be easily recognized by its conical shell 5-6 cm. High. Keeping it out of the pond entirely is almost impossible. Limnaea are hermaphrodite or bisexual. This means that not only can a ‘male’ and ‘female’ reverse their roles at will — they often do during courtship, especially if two snails are joined by a third — but a single snail can fertilize its own eggs. The implication is obvious. If one Limnaea gets into your pond, it can quickly raise a colony, laying egg capsules as long as itself and containing up to 300 eggs. Limnaea nearly always succeed in entering new ponds, either the snail or its eggs being carried in surreptitiously on aquatics or marginals. But there is no need to attempt to eradicate them, even if that were possible; keeping down their numbers will solve any problems. The Ramshorn Snails are often recommended for ornamental ponds because they do not eat lily leaves and the like. They have shells which are not conical like Limnaea, but are flat. It is worth introducing the Great Ramshorn, Planorbis corneus, a red-blooded snail about 35 mm. Wide, or its more decorative relation, Planorbis corneus rubra which has reddish rather than a black or brownish shell. Under suitable conditions these snails can breed at a prolific rate while under others they may not succeed in breeding at all. One can only try introducing a few and seeing if your pond has the right conditions.

Mussels too are particular about their en-vironment. They require the presence of mud. Where plants are rooted directly in the soil in the base of the pond the mussel offers a hazard. When it moves round it tends to uproot oxygenators in its path. (Their movement can be curtailed by building up a circular wall of stones which they will be unable to cross.) In their favour it can be said that a mussel continually siphons water while feeding off the algae. In this way a few mussels can be a great help in keeping a pond clear. The contention that a dead mussel offers a serious threat of pollution is probably exaggerated, unless one is talking about a sink pond or the like. But if you want to introduce mussels into your pond, you would be well advised to introduce one species only. That is the Zebra Mussel, long and is banded in two shades of brown. The larvae of this mussel do not attach themselves as parasites on passing fish as some mussels do; and the mature Zebra Mussel is not liable to uproot plants.

No risk is attached to the introduction of frogs. And no creature, to my way of thinking, adds a greater sense of homeliness to the garden pool. Their appearance in the pool every spring to breed, the pleasant, often frenetic activities of the tadpoles, the occasional hopping and prancing of the young frogs when disturbed in the undergrowth, all add to the sense of the pond as a centre of life. But not everyone will agree. About the Common Frog (Rana lemporaria), the Edible Frog (Rana esculenta) or the Marsh Frog (Rana ridibunda) most people have a very decided opinion. They are found either delightful or repulsive. Their shiny skins in muted colours, their squat bodies and sad liquid eyes are not found equally appealing by everyone. If you find nothing especially attractive about these creatures,tolerate one of the species for its usefulness in eating pests.

In Britain, the frog population has been drastically reduced due to the drainage of areas of marshy ground during agricultural and urban reclamation. School biology lessons have made children everywhere familiar with frogs, and in North America the common species is the Leopard Frog (Rana pipiens).

This versatile frog can stand extremes of temperature and is found as far north as Canada and as far south as Mexico. As the name would imply, all Leopard Frogs are heavily blotched or spotted, but their overall colouring varies from grey through green to brown. The Leopard Frog grows to about 12 cm. In length and like the massive American Bullfrog (liana catesbeiana), 20 cm. Long with legs up to 25 cm., it is renowned for its prodigious jumping ability. A good specimen of Leopard or Bullfrog in energetic mood can leap a distance of 1.4 m. and more. The Bullfrog has the unusual characteristic of guarding its tadpoles which will cluster round the parent for safety. Such cautious behaviour is probably necessary as the tadpoles may remain as tadpoles for up to three years, and that is a vulnerable stage in a frog’s life. Adult Bullfrogs will spend their lives in or close to still water, unlike the Wood Frog (Rana sylvati-ca) which favours damp woodland areas, except when visiting ponds in spring to breed. It grows to little more than 8 cm. In length and is widely distributed through the south-eastern states of America to as far north as Alaska. The colouring of the Wood Frog is very variable, ranging from brown, black and yellow to a pinkish colour. Obviously, the Wood Frog is suited primarily to ponds with a natural woodland setting, and the Bullfrog is rather too large for the small garden pond.

Where space and food supply may be limited, a more congenial species and one common to ponds and streams in the north-eastern states is the Green Frog (Rana clamitans melanota) which may grow to no more than 8-10 cm. Despite its name it can be brown as well as green and is blotched. An even smaller version, the so-called Bronze Frog (R. clamitans clamitans), is found further south.

The American Toad (Bufo americanus) deserves respect for its voracious appetite for mosquitoes; while the Common Toad (Bufo bufo) and the Natterjack (Bufo calamita), both native to Europe, have a useful diet consisting of caterpillars, beetles and other pests. So does the Common or Smooth Newt, Triturus vulgaris 6-8 cm. Long and widely distributed; and the Palmate Newt, Triturus helveticus, which is widespread in Western Europe but less easy to find. The hind feet of the male Palmate are webbed and his tail ends in a thin filament. The Great Crested Newt, Triturus crislatus, is the largest European species, growing 12-16 cm. Long. It has a rather warty appearance. Secretive, agile creatures, newts come to the pond to breed in spring or summer, as do toads. The Great Crested Newt is the only newt which may remain in the pool to hibernate during the winter. The others leave after breeding and may roam far and wide. They are most likely to be seen in hot weather when they leave their secret haunts in water to sunbathe. There can hardly be a child who is not enthralled by their appearance, especially in spring when the males are at their most colourful. All newts shed their skins from time to time, rather in the manner of snakes but with greater ease. Sometimes an entire transparent coat is to be seen floating in the water, that is, if the newt has not devoured it. Newts can sometimes be caught by drawing a worm on the end of a piece of string through the water of a wild pond. Often a newt will hold on to the worm and it can then be brought to the bank. Newts make excellent aquarium pets where their mating ritual can be observed and the females’ habit of folding the leaves of submerged water plants over each individual egg can be watched. They are best returned to the outdoor pond or to the wild in mid-summer. In America, the Japanese newt, Cynovs pyrrhogasler, has become a popular pet.

If you intend keeping Veiltails and Black Moors an aquarium is almost essential. These delicate fish (like many other hybrids) require comparatively high temperatures and should be over-wintered in an indoor aquarium. You could also bring in the young fry of the gold-fish as a means of separating them from their predatory elders. And there is the added advantage that with an aquarium there is no closed season. Instead of your fish hibernating, hidden in the depth of the pool, you can enjoy their graceful lives and those of many other creatures in your own house during the winter, and at close quarters.

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