Feeding koi pond fish

Pond fish such as koi, gold fish and shubunkins are all related to the carp which is naturally a grazing fish, constantly feeding as it picks its way through the silt and debris in a pond. They do not have a stomach, and do not digest single large ‘meals’ effectively, but rather digest many small mouthfuls throughout the day. The ideal way of feeding pond fish can be compared to the advice given by our dentist when recommending how often we should brush our teeth. The more frequent, the better, with 3 times a day being recommended. Any less frequent is not as good and twice a day is the bare minimum.

Keeping fish is unlike keeping any other animal in that the food we feed is not simply being consumed by the fish, but will also potentially affect the fish’s environment. We should get into the habit of thinking that we are not simply feeding the fish, but feeding the pond, and what we feed will have a direct effect on the pond’s water quality and hence the health of the fish.

At the Nishikoi Information Centre, we hear of more fish being harmed by over feeding than through starvation. In fact the harm comes from the poor water quality (from over feeding) rather than the fish becoming overweight. Fish are so much more efficient at using food than other pets that they can go several weeks even in the summer without food and not come to harm.

Fortunately, they will be in no danger of becoming dehydrated! Fish should be fed on a basis of little and often, offering what they will consume in 5 minutes. Any excess food should be removed with a net and your subsequent rations altered accordingly.

Food types

The pond market has seen a significant expansion of different foods available. The types of food can be described by:-

1. Their physical appearance

2. Their nutritional value and quality

1. Physical appearance

Whatever brand is used, there are essentially 3 different forms in which pond food comes.

- Flakes.

An assortment of coloured flakes that are blended to offer a complete and balanced diet. Although they are more popular in the indoor market, (where they don’t get blown away), some pond keepers use flake to feed smaller pond fish. In addition, they do have a tendency to sink, which also enables deeper water fish such as tench (and other shy varieties) to gain their daily food.


These make up the bulk of the pond food market on account of their versatility. Available in a wide range of sizes from 1mm for 2 inch fish, up to jumbo pellets for jumbo fish.

As the vast majority of pelleted diets float, fish are encouraged to feed at the surface (so we can inspect them at close quarters). This also allows us to easily judge how much food to feed, removing any uneaten pellets.

More recently, sinking pellets have become available, for bottom dwelling fish such as tench and sterlets. These must be used with great care, and only when you can safely judge how much food those fish will easily consume. With a sinking pellet, any uneaten food will drop to the pond bottom and break down, polluting the pond water.


Produced in a similar fashion to pellets, food sticks are longer than pellets and are generally less dense. They will usually soften up quite quickly enabling even the smaller fish to nibble away at them.

2. Nutritional value and food quality

Although many diets may look the same, formulations and performance of diets will vary greatly. Not only will they vary between brands, but brands will also produce a number of diets in their range, – from low to high protein, from staple to colour enhancing.

Read the food packaging carefully to identify what foods offer the characteristics you want. Things to look out for are protein level, colour enhancing properties, and Vitamin C content. It is also useful to ask the aquatic outlets what they use on all of their valuable stock on the premises.


FAQ’s – Feeding.

1. Competition at Feeding time. Competition between fish at feeding time can be quite intense. To ensure that each fish is able to feed, offer a range of pellet sizes and even try a sinking pellet for more timid fish, but be careful not to over feed.

2. Holidays. A typical 2 week holiday may apparently present some feeding concerns. If the pond is well planted and has a typical stocking level, then fish will manage satisfactorily over a 2 week period without food. In other cases where you feel they would deteriorate without food, (and you would appreciate a neighbour keeping an eye on the pump, water level, etc.), then put some pre-packaged portions to one side for them to feed each day. This will prevent the risk of them being overfed by a well-meaning neighbour.

3 As autumn approaches, when do I stop feeding? As autumn approaches and temperatures drop to below 14oC, a wheatgerm diet should be fed. However, it is still necessary to decide when to stop feeding completely. From experience, the best judges of this are the fish themselves. If you have ensured that they have fed well over summer, then you need not worry that they will have the reserves to overwinter well.

Kill blanketweed and string algae.