Looking After Koi Carp

Looking to start keeping koi carp? This simple guide tells you all you need to know to get started looking after these stunning pond fish. If you have ever seen orange and yellow shapes moving below the surfaces of ponds, chances are you have clapped eyes on a koi carp. They are a striking breed of large ornament fish, hailing from China and Japan. Koi carp are often a patchwork quilt of colours, their bodies containing yellows, blacks, oranges, reds and white. This is no natural accident; koi carp have been selectively bred to produce different colour patterns for centuries.

Koi carp are one of the most popular pets in the UK, with many calling garden ponds home. However, the competitive world of koi is big business. Showing off your quality carp at competitions is the epitome of success for some koi enthusiasts and those mature fish with unique colours and markings reign supreme. The most desirable fish can fetch prices into tens and thousands of pounds!

If you are interested in getting some koi carp of your own, it must be remembered that they are not your common goldfish. They aren’t complicated, expensive, or time consuming to look after, but you do have to be more involved than with other pond life. The information below will allow you to prepare perfectly for the arrival or your carp, and ensure they are kept healthy and safe.

A Perfect Koi Carp Environment

If you think a small pond net will cut it for koi health checks, you are mistaken. These ethereal fish can grow up to four feet long, depending on species. Therefore, you must ensure your pond is of substantial size. If you keep koi in ponds that are too small their growth will become stunted, resulting in health problems and a poor quality of life.

It has been known for some individuals to house their koi in tanks and aquariums. Although this is perfectly legal, it is frowned upon in the fish world as these facilities aren’t as fulfilling as having a large pond to swim around in. A general rule of thumb is the larger the pond, the happier the carp. Don’t forget to have a comprehensive filtration system – koi carp expel a lot of waste!

Koi carp are cold water fish and generally don’t require a heater in their pond, but this is something to keep an eye on in the winter months. To make is easier for your fish to regulate their body temperature successfully through the seasons, ensure your pond is at least 1.5 meters deep.

Water Quality

The water quality of your koi’s pond is extremely important. If it is not properly maintained and toxin levels managed, their health could deteriorate rapidly. As a koi owner you must have a pH testing kit to hand to monitor the water quality of your pond on a weekly basis. This will ensure it is safe for your fish. Also, once a month, you will need to take out 10% of the pond water and replace it with fresh. This will reduce the levels of ammonia, nitrates, and other toxins in the water. Having a high spec water pump for circulation and a filter to remove mess and toxins is essential for keeping healthy koi.

Furthermore, you must make sure that there aren’t too many fish in your pond. Overcrowding can be a real issue and, as a general rule, there should be 10 gallons of water for every inch of fish within it. To figure out the amount of fish your pond will home happily, you will need to have a rough estimation of the volume of your pond.

Feeding Your Koi Carp

Surprising to some, koi carp are omnivores. This means that eat a diet consisting of vegetation and meat. Most owners feed their koi carp a high-quality complete food; this is the easiest and ensures your carp are getting the correct nutrition. Koi will soon pick up the time they receive their meals, and will happily come to the surface and wait to be fed!

Lots of owners thoroughly enjoy feeding their tame carp treats by hand. They particularly enjoy peas, melon chunks and different varieties of lettuce. However, make sure never to overfeed your koi. It can easily be done, as feeding them by hand is a great time to spend with your fish.


The bright and unique colours of koi carp make them a shining beacon for predators. Even if your carp are kept in a pond in a residential area, they are still at risk of being seen as food. Keep an eye on your pet dog or cat, they have been known to get a little over zealous when popping a paw in the pond. Herons and kingfishers particularly like a carp snack, and fitting a net over the surface of your pond will help keep your fish safe. The common garden nemesis of chickens and rabbits around the country is the fox and koi are not safe from their claws either, particularly when basking near the surface of their pond on warm summer evenings.

Life-Span of Your Koi Carp

Around twenty years is the average lifetime of a koi carp. But, if they are looked after scrupulously, they have been known to reach fifty to seventy years. The oldest carp in the world was recorded as over 200 years old, and some breeds of koi can reach grand old ages.

Keeping koi carp is a long-term commitment and potential owners should think carefully about the home and living situation. If you needed to move house or relocate the fish, would this be feasible? Although morbid, be prepared that koi carp may outlive their owners and they will need somebody to take them on.

Looking to start keeping koi carp? This simple guide tells you all you need to know to get started looking after these stunning pond fish.