New pond Syndrome

As the original swimming pool provided more space than I required for the pond I also built a quarantine/hospitalisation pond and two chamber filter at the same time. However at the time I did not complete the quarantine system as it was not waterproofed when the main pond and filters were fibreglassed. The budget would not stretch that far. Consequently for the last two years Laura and I have had to live with this empty concrete hole being 12 ‘ by 6' by 4' deep with 2 filter bays each 4' by 4' by 4' deep. Not only has this not exactly added to the aesthetic appeal of our garden but the hole regularly partly filled with rain water and all manner of decaying vegetation and aquatic insects took up residence not to mention two frogs who had been removed on numerous occasions kept returning despite the difficulties they encountered of getting passed our three dogs, avoiding the main pond which they would have to pass within inches of and risking life and limb with the 4' leap into the concrete lagoon.

In Spring of this year we decided to finally complete the pond. By now our friendly frogs had so liked their concrete home that they had mated and we had hundreds of tadpoles preventing me from simply pumping out the sludge like contents of the pond. I spent most of one Sunday in April catching tadpoles and transporting them some 3 miles away to a suitable natural pond. I just hope they take to their new home and switch off that radar system that keeps bringing them back to me. Otherwise we might just wake up one morning to the sight of 300 or so frogs that think they have found the holy grail.

Since the quarantine pond will rarely house many koi and is in any event boringly rectangular in shape I initially built a concrete block shelf at one end finishing 12 inches from the pond surface level in order that I can locate a selection of aquatic plants to soften the overall appearance. This done my main decision was to decide on the most suitable form of waterproofing. I planned to use G4 for this purpose ( as I could do the work myself and I assumed this would be the least expensive method ) but was advised by the manufacturers that it would need two coats of clear G4 followed by two coats of black. When costed out it worked out only marginally cheaper than having it fibreglassed to match the main pond which had been fibreglassed by Mick Whitehall two years previous. Consequently I abandoned the G4 idea and contacted Mick who two weeks later, in early May, fibreglassed the pond and filters in one day.

He made a fibreglass plate the exact width of the filter bay which was fibreglassed into position some 3 inches into the second filter bay to create a perfect transfer port between the two filter bays. Having fibreglassed both my 8000 gallon main pond and now the 2000 gallon quarantine system Mick's parting words were " see you next time when you upgrade to an even bigger pond. " - fat chance, I am not ripping up the garden ever again. So Laura tells me! Sound familiar?

From my "Gardening Which" magazine I located an aquatic plant specialist - Honeysome Aquatic Nursery ( address The Row, Sutton, Nr Ely, Cambs, CB6 2PF ) obtained their catalogue and ordered plants for the quarantine pond. I acquired some second hand filter matting and a quantity of flocor for the filters and purchased a Grundfos central heating pump keeping costs to a minimum. I fitted a home made venturi and an overflow skimmer and pinched an airline from the Hiblow operating on the main pond to provide air down the transfer port. By mid May the system was up and running. I took a small quantity of filter matting from the main pond in order to seed the new filter and also transferred over a quantity of the aquatic insects that reside in the main pond filters and seem to carry out a very useful role in my system by consuming the solid debris that by-passes the main pond vortex filter and settles in the biological filters.

In order to provide a food source for the filter bacteria I moved four koi over from the main pond. These were three "expendable" home bred kohaku ( Laura hates me using that term as she regards all our koi as equal pets whatever their quality ) and a not bad home bred sanke which has baffled us for the last two Winters by swelling up to a sickly condition in late Autumn and contracting back to normal shape in early summer. In fact last Winter the swelling was so great that its scales protruded in classic pine cone fashion typical of dropsy and considerable redness was evident indicating some internal inflammation. We did not expect this koi to survive the Winter but with no other facilities at the time had no choice but to leave it in the main pond and hope for the best. Surprisingly it survived and by the time she was moved into the quarantine pond the swelling was reducing and she was swimming and feeding normally. I am unsure whether her condition is due to a failure to ingest eggs or failure to digest food as water temperatures drop. At least now she can be isolated and separately treated if required.

Having got the quarantine system up and running I visited a couple of Koi dealers and made my first koi purchases for some considerable time - about five years in fact. The dealers I visited had new stocks of 3" to 4" Shiro Utsuri. Although not interested in purchasing any of these I discovered two sole Kumonryu in with them. One a predominately black specimen with an interesting white head and the other a white koi with very unusual symmetrical black strips down each side. Laura and I both have a penchant for Kumonryu but dealers rarely have them and good patterns are even more difficult to find. We could not resist these two young specimens even though they were very small and Kumonryu are prone to significant changes in pattern as they develop. We acclimatised them to the quarantine pond and started feeding after a 24 hours settling in period.

We were pleased they settled in well and appeared healthy. However we made the classic mistake of overfeeding , in an effort to increase size and body weight, when insufficient time had elapsed to establish the new filters. In the course of two weeks the pond suffered a rapid growth of blanket weed which then died off almost as quickly as it arrived leaving bits suspended throughout the pond. This was followed by, you guessed it, pea green algae which prevented us observing the new arrivals . The water started to look sickly, the fish became jumpy and eventually took to languishing motionless on the plant shelf. My years of koi-keeping counted for nothing , this was the classic new pond syndrome koi-keeping trap. I had been suckered by the most basic of koi-keeping pitfalls

Fortunately we had spotted the problem early and remedial action was undertaken without delay. Feeding was suspended, the hose pipe was put on constant drip into the pond to effect a slow introduction of fresh water, and several times a day a portable submersible pump was used to pump water from the main pond to the quarantine system to dilute whatever the water quality problem was. I did manage to obtain an ammonia test kit which recorded a virtual nil reading so I can only assume that the problem lay elsewhere possibly nitrite or PH. However, before I was able to acquire any additional test kits, the water soon started to look better and with it the koi behaviour returned to normal. Its amazing when you have been keeping koi for some years and don't have a supply of test kits you generally know when your water quality is good or bad merely by its appearance and by the behaviour of the fish. But as I discovered it can and probably will catch you out from time to time. So having a full selection of test kits is always advisable. However the real moral of this tale is that I abandoned my regular feeding regime and fish husbandry practices in an attempt to speed up the natural process of fish development in a pond which had not matured. It just shows that tinkering with nature is never advisable! Perhaps ponds should be allowed to mature and Koi left to grow and develop at their own pace without any "help" from the impatient koi-keeper.