I remember the first spring I kept koi. I was eager, the sun was out, and I went straight back to full feeding after months of leaving them alone over winter. Within a week, the water was cloudy and two of my fish were sluggish. The problem wasn't the food — it was the timing.
Pond fish are cold-blooded, which means the temperature of the water directly controls how their metabolism works. Get the feeding schedule right and your fish will be vibrant, healthy and growing well. Get it wrong — even with excellent quality food — and you'll end up with digestive problems, poor water quality, or worse.
Here's what I'd tell anyone with a new garden pond, or anyone who's been feeding on instinct and wants to understand what's actually happening under the surface.
Spring: Starting Slowly and Getting It Right
Spring is the most important transition in the pond feeding calendar, and it's also where most mistakes happen. As water temperatures start to climb, fish gradually wake from their winter dormancy — but 'gradually' is the key word.
Until the water reaches around 10°C consistently, fish shouldn't be fed at all. Their digestive systems haven't yet fully switched on, and undigested food will sit in their gut and cause real harm. It'll also start to break down in the water and add ammonia to a pond whose beneficial bacteria are also only just waking up.
Between 10°C and 14°C, a wheatgerm-based food is the right choice. Wheatgerm is easily digestible at lower temperatures and gentle on fish that are still easing back into normal activity. We use a small floating pellet at this stage — it lets you watch whether the fish are actively feeding, and any uneaten food is easy to remove from the surface.
As temperatures push above 14°C and stay there, you can transition to a higher-protein staple food — the main summer diet. This is when fish are most active and growing, so a nutrient-rich pellet or stick mix will give them everything they need.
Summer: Feeding for Growth and Colour
Warm water means active fish and active digestion. In summer, pond fish can be fed two to three times a day — but the golden rule is only offer what they'll eat within around five minutes. Leftover food breaks down quickly in warm water and will damage your water quality fast.
This is the time to look at what your food is actually providing. Good summer pond food will contain a blend of proteins (for growth and muscle), fats (for energy), vitamins (particularly A and E for immune health), and colour-enhancing ingredients like spirulina or paprika, which help bring out the vivid reds, oranges and whites that make koi and goldfish such a pleasure to watch.
One thing I'd genuinely suggest trying in summer is a variety mix — alternating between pellets and sticks, or using a blend that offers both. Fish are naturally opportunistic feeders and a bit of variety keeps them interested and may improve nutritional uptake.
Autumn: Winding Down Gradually
As the days shorten and water temperatures start to drop, feeding should be gradually reduced — both in frequency and protein content. Once you're back below 14°C, swap back to a wheatgerm-based food. Below 10°C, stop feeding entirely.
Autumn is also a good time to think about the health of your fish going into winter. Well-fed, well-conditioned fish that have had a full summer of good food will build up the fat reserves they need to survive months without eating. Fish that have been underfed or poorly fed in summer often struggle more through the colder months.
Winter: Hands Off the Food
This one is simple but goes against every instinct when you see your fish moving slowly around the pond and wonder if they're hungry. They're not — or at least, not in any way that feeding will help.
Below 4°C, a koi or goldfish's metabolism is so slow that it cannot process food at all. Feeding them in these conditions doesn't nourish them; it just creates rotting food in the water and puts strain on a digestive system that's essentially in standby mode. Beneficial bacteria in your filter are also largely inactive, so there's no biological process working to break down waste.
Leave them alone. They're fine. They'll wake up again in spring — and when they do, you'll be ready with the right food at the right time.
Quick Temperature Reference
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Below 10°C — stop feeding
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10–14°C — wheatgerm food only, once daily at most
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14–20°C — transition to staple food, once or twice daily
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Above 20°C — full summer feeding, two to three times daily
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Dropping below 14°C again — back to wheatgerm and reduce frequency
Walter Products' pond range is designed with this seasonal rhythm in mind. Our Nutri Mix and Variety Super Mix work well as summer staples, while our wheatgerm-based pellets are ideal for the spring and autumn transition. All of them float — which makes it easy to keep an eye on how much your fish are actually eating and remove anything they've left behind.
If you're just getting started with a pond, or you've inherited one and are figuring it out as you go, feel free to drop us a message. We're based in the New Forest and talk to pond keepers every day — it's genuinely one of our favourite things.
