When and how should I feed my fish?

 Natural food

In a pool with an established selection of waterplants and a moderate stock of pondfish, there are likely to be sufficient natural foods (plants, insects and other small organisms) to maintain the fish stocks for most of the time. Any food given will be a beneficial supplement to the natural food in the pond, and will encourage the pondfish to become more tame.

The more fish that are stocked in the pond, the more likely that regular feeding will become necessary. In pools with minimal planting the fish can browse on the film growing on the pool sides, but they will need some feeding beyond this.

Feeding in Spring and Autumn

Pond fish are “cold blooded” and the amount of food needed depends upon their activity, which is closely tied to the water temperature. Goldfish and koi become very sluggish below 8-10 degrees C and it is generally best not to feed them when daytime temperatures fall below 10 degrees C or if there is any night-time ice on the pond. Feeding at too low a temperature can result in food being uneaten and polluting the water, or worse, being undigested by the fish and causing internal problems.
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Changes in temperature have a big effect on fish appetites e.g. a drop from 12 C to 10 C may put fish off their food whereas a rise from 8 C to 10 C may encourage them to look for food. Keep an eye on forecasts and avoid feeding if colder weather is due.

Even when spring arrives, feed only lightly until the weather is reliably warmer. Special foods are available that are more readily digested in cool weather. Follow the manufacturer’s recommendations on when to feed, and use a pool thermometer if necessary, to monitor water temperature.

Feeding during the milder days of autumn can help to build fish up for their winter “down time”, and feeding in the warmer days of spring will help them to recover from the winter.

In the autumn, when really cold weather finally arrives, it is best to stop feeding altogether. Only start feeding again when temperatures rise reliably above 10 degrees C in the spring. Feeding during short mild spells in the middle of winter can hinder rather than help fish, as they can use up energy continuing to look for food after the mild spell has ended. They can usually find a little natural food in these brief breaks from winter.

Summer feeding

As the temperatures rise, fish appetites will increase. In spring and early summer any biological filter system will still be recovering from the winter. It is best to increase feeding quantities gradually so that the filter and pond organisms can adapt to dealing with the increasing amounts of fish waste.

In heatwaves (30+ degrees C air temperatures) reduce the amount of food. These high temperatures are stressful to fish, and pool oxygen levels will be lower.

When and how much to feed

Feed during the day, and avoid feeding late in the evening. When feeding as a supplement to natural foods in the pond, two or three times a week will be ample. In ponds with more fish and fewer plants, daily feeding is in order in the summer, or smaller amounts twice a day. © www.watergardensolutions.co.uk

Only feed what can be taken by the fish in a couple of minutes. Commercial fish foods are concentrated, and if too much is eaten it will pass through the fish only partly digested and then pollute the water. If excess food goes uneaten, net it out to avoid pollution and feed less the next time. It is very rare to find ponds where fish have problems due to shortage of food, but more common to find fish in distress because the pool has been polluted with excess food. Excess food will also make algae problems worse.

If fish unexpectedly go off their food, it might be because they have been scared e.g. by a visiting heron. Other reasons include water quality problems, and fish disease. If they continue to avoid food, it is worth testing the water quality, and examining the fish more closely to see if anything is visibly wrong.

What to feed

There are many good quality pond fish foods now available. Floating foods are generally the most appropriate. Pelleted foods tend to be more dense than stick foods, and less volume needs to be fed. Pick a pellet size appropriate to the size of fish in the pond, erring towards the smaller size if in doubt. Restrict the feeding of the highest protein (“Growth”) foods to the summer months. Only buy what you can use within three months, and keep containers sealed, cool, and dry. Just like breakfast cereal, fish food starts to become stale once the pack is opened. Flake-type foods are ideal for baby fish, but can result in more waste and mess when fed to larger fish.

When on holiday

If you are away for a weekend, fish will not starve as they can browse on natural foods in the pond.

If you are away for longer, you can set up automatic feeders to dose a set amount of food into the pool each day. Alternatively leave a dosing measure for anyone taking care of the pool so that they are not tempted to feed too much food. Never feed extra to make up for a day of missed feeding, it will likely pollute the water. Check that pumps and filters are all clean and running correctly at least a few days before you go on holiday. This gives time to monitor that they have settled down and are still functioning correctly.