Choosing koi pond fish

I’m glad that being tempted isn’t a sin because it happens to me every time I visit an aquatic store, especially one with thousands of pond fish saying ‘take me home’. The feeling is reminiscent of walking through a sweet shop faced with row upon row of candy-filled glass jars stacked to the ceiling – ‘I like them all, but which do I choose?’

Likewise, when we visit an aquatic store, we are definitely entering the realm of the impulse purchase, where even if we have planned to purchase only half a dozen fish, we can easily leave with more.

Yet fish are not merely an ornamental commodity, but animals whose lives depend on our husbandry skills and our pond’s ability to sustain them. Before buying fish for our pond we should go through our own mental checklist to ensure that we make the correct decision for the fish in the shop and those back at home.

There are essentially 2 sets of criteria we should compare our prospective purchases against before buying and as will become clear later on, it is always better not to buy fish (but return later to buy) than to buy in haste.

Assuming that your pond is sufficiently large and well filtered for new fish and that it is sufficiently mature to cope with any additional feeding and waste, then the 2 areas to asses your purchase against are: a. Fish quality and b. Fish health.

a. Fish Quality.

When viewing fish, your choice of fish is likely to be limited by your budget. When looking at koi for example, their size, grade and variety will determine the asking price. This is not to say that less expensive koi when compared to others of a similar size are any worse as fish, but that those koi do not exhibit the more desirable pattern and colouration as found in higher grade specimens. Nevertheless, buying koi is a very personal and subjective issue, as tastes will vary and not all of us are interested in having our fish judged against other koi in pursuit of a prize.

Buying fish has been compared to buying a house in that we tend to know in the first few seconds whether we like it or not, and that is purely down to our own personal taste. If you like it and you can afford it, then buy it. It’s for your pond and you’re the one who’s going to be nurturing and admiring it for years to come and you should not feel too swayed by what the ‘books’ say is a good fish.

If you are purely interested in adding to your collection in a koi-only pond, then it is likely that your choice will also be affected by your existing koi. As there is a finite range of koi varieties, koi keepers generally try to collect a specimen of each variety. This will create a stunning visual display of contrasting colours and patterns and can help you to formulate your shopping list. Furthermore, it makes choosing each specimen all the more important if you are limiting yourself to one of each variety.

Fortunately, if you are choosing goldfish (or varieties of goldfish) for your pond, such complexities of pattern, grade and even breeder are less of an issue (unless you are buying to breed or show) and you should feel unhindered in the fish you choose. Who is to say you have good or bad taste. If you like it, then buy it.

Fish Health.

Compared to choosing the pattern or variety of fish, fish health is far less a matter of personal taste when considering which fish to choose for your garden pond. In an ideal world all fish that are displayed for sale would be healthy and disease-free. However, for a number of reasons, some of which may be beyond an aquatic store’s control, fish can deteriorate rapidly (in a matter of hours) especially when systems are heavily stocked.

In the same way you’d look for key ‘condition indicators’ before buying a second hand car, there are a handful of criteria that each fish must satisfy before you commit to purchasing it. Unlike choosing  fish for their  colouration or pattern, if a fish is diseased (even if you like it) you should not buy it. Not only is your investment likely to be short-lived, but it may well threaten the lives of the fish back in your own pond.

Things to look out for:

1. Fish that are active, alert and swimming. Although difficult to spot when viewed from above, a handy indicator as to whether the fish is ‘happy’ is to check that its dorsal fin is erect (similar to assessing the fundamental condition of a car by checking the exhaust’s emissions). Fish should not be ‘hanging’ just below the surface or huddled in a corner. They should give the impression that they are ready and eager to feed.

2. Fish should be responsive to your presence. In some instances (particularly common in heavily stocked display tanks) fish will swim en masse towards you, open mouthed and expectant of food. If fish appear more interested in keeping themselves to themselves and do not react to your silhouette or shadow (even if it is to swim away) then that is a sign of ill health. In a similar way, if fish are more intent on gasping at the surface than behaving normally, this too is a sign that the fish are not in the best condition. Move on to another tank or vat.

3. Fish, unfortunately, can suffer from a range of diseases and health problems, many of which appear externally to the fish and can be easily recognised and diagnosed. Most diseases are accompanied with tell-tale changes in behaviour (such as sulking, gasping, flicking, scratching and flashing) but a few others do not and should be recognised on close inspection of the fish. Health issues can be put into 2 groups. Those that are infectious and those that are the result of bumps or abrasions (such as torn/split fins or missing scales).

All diseases can be treated (although that should not be your responsibility when buying fish) while those with bumps and abrasions will heal in a healthy pond and these (if still on show) may even be available at a discount.

Features such as ragged fins (fin rot), protruding scales or broken skin (bacterial infection), scratching and flashing (external parasites), appearing as though it has been dusted with sugar (whitespot) or cotton wool-like growths (fungus) are all symptoms of diseases that will threaten your existing fish (and should be pointed out to the retailer). Look for fish that are free from blemishes, fins are intact and the skin, scales and fins are clear and unbroken.

4. Ask whether the fish on sale have benefited from a period of quarantine/acclimatisation. Those fish that are not farmed locally will usually have undergone a trip from the other side of the world, and will benefit from a period of rest and acclimatisation. If you purchase recently imported fish that have been even mildly stressed on their journey, then health problems may manifest themselves in your own pond, breaking out in disease a few days later. Many retailers will offer acclimatised fish for sale (publishing the fact with signs), taking an element of risk away from your purchase. Quarantining presents a considerable cost for the retailer in underwriting risk, cash flow and backroom resources. If you have a choice, choose acclimatised stock as this will go some way to pay back the retailer for the additional services he has provided for your benefit.

5. The final aspect worth checking prior to choosing fish is the water that the fish are being kept in. Ideal water should be well aerated, recirculating, colourless and odourless, having a real sparkle to it. You should be able to detect if systems are overstocked, or there is a filtration or disease problem by observing the water. Milky water suggests a problem as does water with a blue tint (medication). If the water smells or doesn’t appear too ‘sweet’ then this too is likely to precede health problems that may only manifest themselves later in your pond.

The vast majority of fish offered for sale are in tip-top health, held in some of the finest tank and filter systems. However, you owe it to your existing fish back home to carry out a little detective work prior to purchasing fish for your pond. Once you are satisfied that the fish will make healthy additions to your pond, and that, of course, they are the size and variety you want, there is only one thing left to do – and that’s to part with your hard-earned cash.

Kill blanketweed and string algae.