Q & A About Koi Fish


DIY and how-to

Two koi fish swimming in a pond, seen from above with the fish covered in blood-red markings.

Q & A About Koi Fish

How many fish can I fit in my pond?

With Koi that’s an easy question to answer. We recommend no more than one fish per 1 000 litres of pond (excluding filter) volume.

What size filter do I need?

Koi grow to the size of their bloodline. Japanese Koi have the biggest growth potential of all Koi. This means that the cute little babies you buy now will grow exponentially within a year. Before long you will see just why we recommend just one fish per 1 000 litres.

Japanese Koi from quality bloodlines all have the potential to grow to 70cm as a minimum, 80 cm as the norm and over a metre on the odd occasion. A 70cm Koi is a BIG fish. It will eat a lot and produce a lot of waste. Ten Koi in a 10 000 litre pond will require superb filtration to keep things stable. Adding a few extra fish can seriously strain even the best filtration systems. So, it’s generally a good idea to go for fewer fish.

When it comes to filtration, it is best to specify two independent filtration circuits. This is purely as a back-up mechanism so that if something goes wrong with something on the one circuit you will still have the second one operational and so the chances of pump failure, or a broken pipe on your kit are minimised. The golden rule when it comes to filtration is that when in doubt, go bigger. It can only save you time, money and headaches in the long run.