Choosing Fish for the Garden Pond
While plants make the major contribution to the appearance of the water garden, fish bring it to life. They also play an important part in the ecology of the pool, feeding on aquatic insect life and depositing detritus which, ultimately, will benefit the plants.
THE ROLE OF FISH
For the practical water gardener, the most important role for decorativeis the control of and damaging, aquatic insect pests, such as larvae. Even if you have no particular liking of fish or inclination to keep them, you should consider them carefully as an essential part of the biology of the aquatic environment.
In the pool, submergedin the presence of sunlight absorb the carbonic acid gas produced by fish and other aquatic fauna. Aided by the green chlorophyll in their leaves, the plants convert this into nourishment and, in the process, produce oxygen, which is dispersed into the water for the benefit of the fish. Therefore, for the well-being of a water garden, it is desirable to have reasonable and balanced quantities of both fish and plants.
Apart from the obvious ecological benefits of having fish in the pool, there are aesthetic ones, too. Watching colourfullazing in the sun or dashing among the floating foliage of waterlilies can be very therapeutic. The antics of the more lively characters like golden orfe, leaping for flies or playing in the spray of a fountain or the turbulent waters beneath a waterfall, are equally pleasurable, while the ritual of feeding can become compelling entertainment. After a period of from one particular point at the pool edge, they will appear at the surface in response merely to a footfall or a shadow cast across the water.
WHICH FISH WILL LIVE TOGETHER?
One of the most troubling aspects of stocking a pool is selecting the fish.
Newcomers always seem to have heard horror stories of fish eating fish, and are fearful of an almighty power struggle in the pool if the inhabitants are not chosen with extreme care. In reality, however, there are few rules to worry about when it comes to choosing particular sizes or varieties, though it is probably a good idea to steer clear of the various cold-water catfish.
Several species of ‘catfish’ are sold for ponds, and while all are innocuous when young, on attaining maturity they can cause carnage in the pool. They begin their lives eating aquatic insect life and snails, but end up eating fish fry and tearing at the tails and flowing fins of fancy goldfish. Even the common goldfish and shubunkins are not completely immune to their attentions. If introduced to the pool, they will lurk on the floor or among the submerged plants and be almost impossible to recapture unless the pool is emptied, so steer clear of these fascinating, but destructive, fish.
All the other fish will co-exist quite happily. It is true that an adult fish will eat spawn and sometimes small fry, but any fish over 5-1/2cm (2in) long should be completely safe from predation. This applies to all the carp family, including goldfish, shubunkins and tench.
All traditional domestic goldfish are suitable for an outdoor pool. There is a common misconception that the goldfish of the bowl or aquarium is, in some way, different from that ofpool. While size may play a part in this misunderstanding, in fact they are the same. A goldfish kept in a bowl may remain small, but that is because of the confines of the bowl. Once introduced to the garden pool, goldfish will soon grow and, irrespective of their size, will mix happily with their cousins.
WHEN TO INTRODUCE FISH
Most new pond owners will want to introduce fish to the pool quite quickly, especially if being pressured by children. However, resist adding fish to a new pool for at least a month after planting the last plants. They really need time to become established, even if you are only going to introduce small fish. These can still be extremely boisterous and may disturb freshly planted plants, especially submerged, as they dig in the substrate looking for food, or tug at tender new growth. Once plants have been disturbed, it is very – difficult to re-establish them without emptying the pool and the baskets. The deposit of soil or compost from the disrupted will swirl continuously in the water as the fish dart about and dig for food, leaving a debilitating deposit on the foliage of submerged plants. So be patient and let the plants become properly established before choosing fish. Ideally, you should add only two or three at a time at approximately fortnightly intervals.
CHOOSING YOUR RETAILER
These days, the most common method of purchasing fish is by visiting anspecialist or garden centre. It is as important to choose a good retailer as it is to choose healthy and contented fish. Obviously, one goes with the other, but if you are buying fish for the first time, you may not necessarily recognize the most suitable establishment. If you have any doubts about where to purchase fish, visit a number of outlets. You may find considerable differences in housing methods, hygiene and price, the latter not necessarily being related to either of the former.
Most retailers of pond fish keep them in large fibreglass or plastic tanks or aquaria, the individual fish being graded according to size and variety. Often large numbers of fish are kept in relatively crowded conditions. Modern filtration and husbandry techniques ensure that theis ideal and does not adversely affect the fish. Avoid buying fish from retailers where you have observed numbers of dead or unhealthy fish. Although you can select healthy looking fish from such tanks, they may he carrying disease organisms that can pass to your own collection.
Perhaps the most important factor to consider when selecting a retailer is his or her knowledge. This can be invaluable and will help you to choose the right foods, treatments and plants, as well as the right fish.
THE GUIDING PRINCIPLE
The majority of decorative pond fish sold for domestic use are imported. While some are bred in Italy, Germany and the UK, and considerable quantities raised in the United States, the leading producers are the Far East and Israel. The fact that they may have come from tropical climates does not have any effect upon their hardiness or suitability for the outdoor pool. However, it is worth asking how long they have been in the country, as a journey half-way around the world can be very stressful.
If the retailer has had the fish in stock for a week or more, they will probably be fine. Sometimes their body colour will give an indication of the amount of time spent with the retailer, especially in the case of goldfish and shubunkins. Usually, the brighter the colour, the more recent the stock. Always favour a pale red or salmon coloured goldfish, rather than one that is brilliant red, as the paler ones are likely to have been with the vendor longer, which means that they will have had time to become established and, therefore, are less likely to be troubled by their journey home with you.
There are certain principles that apply to selecting any healthy fish. Erect fins and bright eyes are the best indicators of good health, together with an absence of scale damage. Occasionally, large fish will lose a scale or two while being transported, but smaller fish should be intact. Do not worry too much if you buy a large fish that is missing some scales. Eventually, these will be replaced, and provided you treat the pool with a commercial fungus treatment, there is unlikely to be any secondary infection.
If the fish you are considering look very lively, this is not necessarily a sign of good health. Exceptionally lively antics, such as rubbing against underwater objects or jumping out of the water, may indicate that the fish is being irritated by an external fish parasite or that water conditions are poor.
Lethargic fish should be avoided, particularly those that sulk on the bottom of the container or remain isolated from the others. You should also avoid individuals that display small spots on the fins or tails. These are often associated with the disease called white spot which, unfortunately, is not uncommon in fish that are kept in crowded conditions, even though most responsible retailers maintain a regular treatment regime and are constantly vigilant. White spot disease is not a welcome ailment in any water garden, even though it can be controlled. However, do not confuse the white nuptial tubercles of mature adult male fish with this disease. The tubercles are white, measle-like spots that occur on the gills and head, and are particularly pronounced in male goldfish and shuhunkins..
The shape, size and colour of the fish you select are very much a matter of personal choice. Avoid any fish with uncharacteristic shapes, such as carp that have larger than normal heads and tench with almost black bodies and a propensity to swim just beneath the surface of the water.
HOW TO INTRODUCE FISH
The important point to consider when introducing fish is the difference in temperature between the water in the bag and that in the pool Usually, the water in the bag will be much warmer, and tipping the fish out into cold water can stress them, leaving them susceptible to disease.
It is important, therefore, to float the bag on the surface of the pool for 20-25 minutes before releasing the fish. If you leave the bag fastened with its rubber band while you do this, observe the fish carefully; the sun shining brightly on it can make the temperature inside soar in a matter of minutes, so the bag should be opened and the top rolled down to make a float. Where possible, float the bag in a shaded area of the pool. Once you are satisfied that the water temperature has equalized, gradually add some of the pool water to the bag to equalise the chemical differences between your pool water and the water from your dealer, and then gently pour the contents of the bag into the pool.
On their release, the fish may well swim to the bottom of the pool and be reluctant to feed for several days, but don’t worry — this is normal behaviour due only to the fact that the fish are not confident in their new surroundings.