Koi keepers the world over have to be vigilant if they want to protect their stock from disease – and the best way to do this is with a quarantine pond.
Quarantine is defined as enforced isolation, usually to contain the spread of some kind of disease that is considered dangerous. The word, which comes from the Italian ‘quaranta giorni’, meaning 40 days, originates from 1377 when a 40-day period of isolation of ships and people was enforced to prevent the spread of the plague, or Black Death in the city of Dubrovnik.
The quarantining of new Koi fish has always been a recommended practice as prevention against the spread of common parasitic and bacterial infections and has become even more important in recent years since the worldwide spread of Koi Herpes Virus (KHV). Koi, like all animals, can suffer from and carry disease and an apparently healthy fish may be harbouring some form of disease that could pose a risk to an existing population.
A good quarantine regime is as important, if not more so, to Koi breeders and dealers as it is to hobbyists. All Koi farms need to bring in new brood stock to continue the improvement of the quality of the Koi fish they produce. For this reason they need to follow the same basic quarantine procedure as any hobbyist.
Farms which buy fish in to grow on and resell at a later date need to be doubly sure that these new fish are free from disease, as they will most likely be missed with existing stock before being sold on.
Dealers have he same responsibility to their customers as breeders do to ensure that they have done everything they can to provide properly quarantined fish that are as disease-free as can reasonably be expected. They should always carry out their own quarantine regime every time they bring new fish into their establishment.
If money were no object
In an ideal world, every Koi keeper would have their own quarantine facility and would quarantine every new fish they bought before introducing it to their pond. If money and space were no object, a hobbyist’s quarantine facility would consist of a separate insulated building that housed 2 dedicated quarantine tank of approximately 2,000 gallons – this would comfortably cope with any size fish that might be purchased including a bottom drain and leading to ‘a more-than adequate filtration system.
Quarantine filtration needs to be able to react to large fluctuations in fish-stocking density and medications. The system should include a UV unit to help reduce the bacteria count within the circulated water and there should be a dedicated air pump to provide adequate aeration during medication procedures ~ ideally, the pump should be drawing air from outside the building. Either the air inside the building or the water should be heated – heating the air reduces the risk of any condensation building up.
The building should have its own water supply and be equipped with its own nets and bowls. Gloves should be used at all times when handling fish, water or equipment in the building so as to reduce the risk of transferring any disease to other Ponds. The system should contain some naive fish, or ‘canary Koi’ ~ healthy fish not previously exposed to disease which serve the purpose of keeping the filtration system active, provide company for any new fish that are introduced and which also ‘act as ‘indicator’ fish if there is any viral disease present in the introduced fish.
The real world
For the great majority of Koi keepers, however, the next step down from the full quarantine building would be to have a dedicated tank of 500 gallons or more and a filter system that could be insulated to enable temperature ramping to be carried out. The drawback is that the tank should be covered to retain heat which makes observing a fish’s normal behaviour difficult.
The other alternative would be a collapsible tank, which has the added advantage of being easy to store away when not in use.
To filter a 500-gallon tank our personal recommendation something like an Evolution Aqua Eazy Pod, which is designed to cope with a 2,000-gallon pond (maximum) and will therefore be better able to withstand with the unusual stresses it will be placed under. This should be used with a pump that will turn the pond volume over every one-to-two hours. The UV unit should be a minimum of 30W, with 2 40lpm air pump providing aeration to the
There are several ready-made packages on the market and as long as you can find one that meets these requirements as closely as possible, you should be fine. If you have the skills to make your own quarantine system you could build something tailored to your own personal needs that would fit into the space that you have available – and this should only cost you a few-hundred pounds.