How to avoid overstocking your pond
Each Christmas, with only a few days before Christmas Day, supermarkets are absolutely packed and so are our trolleys, full of choice items that will make the festive period a happy one. Most of us are probably guilty of over-buying at this time, getting carried away, only to discover how much we have overindulged when we get home to unpack the groceries. Our cupboards, fridge and freezer can't take any more and we have to resort to stashing what is left in the spare bedroom. - We've overstocked!
Overstocking is a relative term, describing the quantity of a product in relation to the space that is available to store it. Two customers could buy the same number of groceries, one of which struggles to store it all away while the other, having more cupboard space will fit in this relatively small order with ease.
We have a similar consideration when stocking our pond with koi. Each pond is different, and has a different capacity for koi. A koi pond's 'cupboard space' is determined by its ability to safely hold koi, providing them with a healthy environment and giving them space for growth.
There is little point in quoting figures of how many inches of koi can be stocked per square foot of pond surface as this ratio does not take into consideration other factors (such as the size of the koi, filtration and aeration). Yet there is a loose relationship that shows that the greater the surface area, the greater a pond's capacity to hold koi. If two ponds have an identical volume, the one with the larger surface area will accommodate more koi.
A pond's ability to hold koi should not merely be regarded as a function of its physical ability to hold koi, (ie, like storing groceries in a cupboard). A koi pond's stocking rate is determined by the filter's ability to process and breakdown the waste that koi produce. To be more precise, we need to be sure we do not overstock our filter, rather than our pond. This does not merely focus on the biological activity of a filter, but also it's ability to remove solids at the required turnover rate. A pond's water quality management system would also need to provide sufficient aeration for a given stocking rate.
Why should you not overstock?
The fundamental reason for not overstocking is safeguarding the health and growth of all of your koi. If their environment is stocked beyond its capacity to handle a given stock of koi, they will be stressed and therefore made more susceptive to disease
How can you tell you've overstocked?
By taking the problems associated with overstocking, there are two areas to investigate. Having said that, the problems associated with overstocking will soon show themselves rather than you having to actively look for them.
Poor water quality.
As discussed earlier, a pond is overstocked with respect to the capacity of its filter. If you are consistently unable to achieve zero readings for ammonia and nitrite, then you are overstocked. Problems may diminish over time if you have a new filter system (while it matures), but if you have a mature system with problems - your system is overstocked. The awe-inspiring sight of 'koi pizza' in breeders' intensively stocked over wintering ponds would suggest they are overstocked. However, they are adequately filtered and the fish show no signs of stress from being overstocked for a limited period.
Regular problems with fish health.
If your filtration is able to keep on top of the water quality but your koi still experience regular health problems, things may be pointing to stress from over crowding. Even the Japanese farmers only keep their stock at high stocking levels for so long - ready for sale or returning to the mud ponds. Prolonged overcrowding will cause koi stress, resulting in 'long term blues' and health problems.
What can you do if you've overstocked you pond?
Depending on your situation, there are short term and long term measures you can take to alleviate the stress for your koi.
Short term measures:
Long term measure
Having prevented a disaster by intervening in the short term, if you want to maintain your stock as it is, you should immediately start to plan an increase in filtration and aeration provided by your system. Aeration can be addressed relatively quickly but increasing filtration requires more extensive planning. It may take weeks to install and many more weeks to fully mature.
How to solve
Emergency action points to carry out if you discover you have overstocked your pond.
koi pond overstocking stress "water quality" filter
health ammonia aeration filtration growth fish "surface
area" ability stocking
Article Categories ... A to Z | Blanketweed | Koi seasons | Fish health | Water quality | Fish food | New pond care | Equipment | Koi queries | Emergencies | Water testing | Koi answers | Pond aeration | Algae control | All articles list | Blanketweed | How to choose equipment | Pond filtration | Koi Feeding | Goldfish | Pond medication | Koi varieties breeding | 10 steps to a great koi pond | Fish handling | Links to Expert Koi and Goldfish Pond Articles | Article summaries | Preformed liners | Hozelock UK pumps | Blagdon UK pumps | Oase pumps UK | Lotus pumps UK | Solar pumps | Draper UK pumps | Heissner UK pumps | Pond filters & UVCs | Fish food | Fish & water chemicals | Pond vacuums | Water features and kits | Pond & garden lights | Pond nets & netting | Pond tools and clothing | Pond accessories | Pond books | Pond plants and planters | Koi farming |