How to Use a Koi Filter

Owning a koi pond is not hard work but what little work there is must be done if the fish are to survive. The water quality of the koi pond must be kept high at all times and tested on a weekly basis. In order to make it easier to do the work you must spend time planning your pond long before the fish arrive and install the necessary equipment to the necessary standard. One of the most important things is to have a good filter to remove koi waste.

There are two reason why looking after koi is necessary. Firstly, koi were carefully bred for their aesthetic colors more than other feature and this selective breeding has weakened their immune system and secondly, the koi pond is not a naturally occurring feature. In the wild the volume of water and the current will both dilute the waste and remove it. In the koi pond this must be added on. Koi produce ammonia from their gills and vents and ammonia is toxic to koi.

The koi filter is a two stage system, one being mechanical and the other biological. The filtering is supported by a pump that may either be submersible, which is best for the small garden pond as it can support a waterfall as well as being quiet, and the more robust recirculating type better suited to large ponds.

The mechanical filters use materials such as sand, beads, and brushes to remove debris that normally accumulates in a pond such as leaves, twigs and paper while the biological filter is designed to neutralize the organic waste from the koi themselves. The mechanical filter will need to be cleaned out regularly and often by the owner. The biological filter is designed to neutralize the ammonia produced by the koi. It does this by using bacteria that change the ammonia into nitrites, also toxic to koi, and then into nitrates, which are only harmful in large amounts. The nitrates are also used to feed algae at the bottom of a pond that produce oxygen from it.

Aeration is also necessary as oxygen is necessary to the life of the pond and to break down waste. Fountains and waterfalls are usually chosen and are supplemented by changes of up to a third of the water every so often. You can test the water’s chemistry using a home kit or by taking a sample to your local pet store. Koi need the water just slightly alkaline, about 7.4 pH though anywhere between 7.0 and 9.0 will be acceptable if it doesn’t change too much.

Despite the importance of making sure the water is clean and healthy for the fish, the task is neither time consuming nor thankless. Koi are expensive fish and you want to protect your investment but the rewards of having happy, healthy koi in your garden and in your life are the reason they are the world’s most popular ornamental fish.