03. How to keep koi. Koi Husbandry and Koi Keeping Skills

Good husbandry skills are an essential part of successful koi keeping and may involve less hands-on work than you may have first thought. Koi husbandry covers aspects of how we handle, interact and even observe our koi, and describes the full range of the control and management activities that we carry out so that our koi will thrive in our pond.

Husbandry skills can only be learnt to a limited extent ‘off the page’ and practical hands-on guidance is necessary to be able to fully appreciate what you’re koi are telling you, and what they require from you on a daily basis. Activities such as feeding and pond maintenance fall under the heading of husbandry, and these are the basics of koi husbandry. The remaining aspects of husbandry involve more instinct or natural ability and these include handling koi, but perhaps most importantly interpreting your koi’s behaviour and responding appropriately to their behavioural signals.

Those that are keen DIY enthusiasts will have learnt the benefit of ‘measure twice, cut once’ when preparing carpentry or pipework. The same advice is true for our hobby, where koi husbandry is a matter of observing twice before doing anything else, especially adding treatment to the pond.

Normal behaviour.

Just as a shepherd may rest on a gatepost to assess the health of his flock, every koi keeper should spend time watching their koi. How else will we become accustomed to normal behaviour? Even though there is such a thing as typical koi behaviour, each pond will cause koi to behave in slightly different yet normal ways. You need to establish what is normal for your pond.

It is difficult to describe in an article what constitutes normal behaviour. But someone who has sufficient experience can, at a glance, judge accurately the current health status of a particular pond full of koi. In those first few seconds, it is possible to gather information from a number of different things that koi are or are not doing. Subconsciously, we will be looking at the following:

Our koi’s reaction to stimuli. Koi will soon detect us as we view them and we can tell a lot by how they respond to our presence. Firstly we should see a response. The koi will readjust their positioning in the pond in relation to where we are viewing them. If koi don’t respond and hang motionless take a closer look.

Body position. Apart from a few exceptional circumstances, koi should always be in motion (however slow). They should certainly not be sitting around on the pond bottom for lengthy periods of time. Watch out for individual koi with a mind of their own, that stubbornly choose to rest while all of the others are cruising, grazing and interacting with each other. Furthermore, koi should not adopt a head down hanging position in a pond nor be found at gasping at the surface. These are definite signs or abnormal behaviour.

Your koi should show a keen interest in feeding. A loss of appetite can indicate a number of different problems, being the early warning system in a pond. You can interpret such behaviour differently depending on whether a single fish is affected or whether all of your koi are on hunger strike.

Koi are just like any other fish (or animal) in that they will be irritated periodically, causing them to scratch themselves to relieve the irritation. The odd flick flash or jump does not indicate a problem and is quite normal behaviour. However, if most of your koi exhibit such behaviour over a day or so, you should interpret this as needing to investigate the source of irritation further. The most likely causes of prolonged or chronic irritation are a water quality problem (high ammonia or nitrite) or an external parasite problem.

Putting koi behaviour into context. Koi are very expressive fish and the finer you can tune into their expressive patterns the better your understanding will be. There can be a risk of us over-reacting to even the smallest of changes in their behaviour, as koi can exhibit a range of unusual behaviour that really is quite natural.

Seasonal inactivity. Koi are adapted for a calendar of seasonal variations, including the course a period of inactivity throughout autumn and winter. When koi lose their appetite or gather on a pond bottom in autumn, this is not unhealthy or unnatural behaviour, but merely this cold-blooded animal responding to a drop in temperature. However, as the pond starts to warm up in spring, make sure all of your koi show the same level of activity, keeping an eye open for any loners.

Quarantine. A period of acclimatisation for koi between purchase and introduction to your main pond is advisable for all of your koi. This will allow you to scrutinise the fish’s behaviour, and also give this well-travelled fish a chance to reduce it stress levels from what may have been an arduous journey from Japan. However, do not be alarmed if your koi shows signs of sulking in his period of solitary confinement. Koi are gregarious fish and generally exhibit a ‘strength in numbers’ approach to feeding. The more densely stocked, the tamer they become the reverse often being true also, especially in quarantine conditions. Fighting or spawning? On more than one occasion the Nishikoi Information Centre has been contacted by concerned koi keepers who are keen to know how they can stop their koi from fighting. Quite surprisingly, these omnivorous scavengers do not show aggression towards each other with this apparent fighting actually being their boisterous spawning behaviour. Males will chase and drive at a ripe egg-laden female (or any fish they suspect is ripe – just in case). Females can experience a lot of physical contact during spawning so keep an eye out for any lost scales or minor abrasions that may require a topical treatment.

Shyness. Your koi may well suddenly exhibit shy behaviour, being less inclined to venture to the surface to feed. This behavioural response is quite natural if your pond has been disturbed recently by the attentions of a heron or cat. Although not life-threatening you should respond to this self preservation behaviour by confirming what the threat to the pond’s tranquillity really is. Prolonged shyness and inactivity brought on by regular visits to the pond by a predator will soon develop into a stress-related, chronic health problem.

Husbandry – Not so hands-on.

Koi husbandry does not necessarily have to be a hands on activity, where you are in danger of feeling that you’re not doing enough for your koi unless your sleeves are regularly rolled up and your hands wet. Less is definitely more when it comes to effective koi husbandry. Having mastered the art of koi watching and interpreting what they have to say to you, you are immediately in the position of carrying out an informed evaluation of the health status of your koi, but from a safe distance. (That’s how your koi would see it, anyway).

Every koi keeper should have a bowl for inspecting their koi and a couple of long-handled koi nets for quickly capturing individual koi. But just because you have this equipment does not mean you must regularly use it. Koi should be handled and netted as little as possible (remember they are assumed you what a predator) as each time you handle them they will be stressed unnecessarily. The art of koi watching is intended to keep an necessary bowling to a minimum.

There are times when it is necessary for you to inspect and bowl your koi on a one-by-one basis. Check that your koi are intact with no exposed wounds or abrasions prior to autumn and likewise, carry out a spring time check for sores and ulcers (especially the ventral abrasions) to confirm your koi have overwintered intact.

Your hands-on husbandry should be directed at your pond’s infrastructure and systems, recognising that these create your koi’s environment which in turn is the single greatest factor that controls and sustains your thriving koi. Regular water and filter maintenance, careful quarantining, well-managed stocking and quality feeding will all work together to enable your koi to thrive in your pond. This will leave you to add the finishing touches of husbandry, by observing, responding and intervening only when required (and as little as often).

Kill blanketweed and string algae.