Independent comparisons. We may earn from shop links. More info

Koi pond air pump size

Updated: 22 October 2026

Two ponds hold a few thousand litres. One is planted, with goldfish. The other is koi. The koi pond air pump size is what changes. This page is that contrast. Plugs, splash ratings and kit versus pump-only stay on the [buying guide](/hub/garden-ponds/pond-air-pump/sub/pond-air-pump-buying-guide). Named picks are on the [best pond air pump page](/hub/garden-ponds/pond-air-pump/sub/pond-air-pump-best), and the table is the [pond air pump comparison](/hub/garden-ponds/pond-air-pump). Figures are Evolution Aqua’s bands and the amazon.co.uk snapshot of 20 October 2026. Peter F. did not run a lab test. A qualifying purchase through our links can earn a commission at no extra cost to you.

Two ponds hold a few thousand litres. One is planted, with goldfish. The other is koi. The koi pond air pump size is what changes. This page is that contrast.

Our top picks

Blagdon Blagdon Pond Oxygenator 1800

Best overall

Blagdon Blagdon Pond Oxygenator 1800
8.3/10about £72.99
View offer
Pontec Pontec PondoAir Set 450, 6 W

Best value

Pontec Pontec PondoAir Set 450, 6 W
8.1/10about £29.45
View offer
Blagdon Blagdon oxygenator kit, 2 outlets

Rank 3

Blagdon Blagdon oxygenator kit, 2 outlets
8.6/10about £38.79
View offer
On this page
  1. 1.Same litres, different fish
  2. 2.Which listing matches which pond
  3. 3.Outlets are not extra air
  4. 4.Warm weather is not a bigger pump by itself

Same litres, different fish

Evolution Aqua uses about 15 litres of air per hour per 1,000 litres on an ornamental pond, and about 200–400 on a koi pond, plus 10–20%. Warm water holds less oxygen, so the band is a summer tool as well as a winter one. A 2,000 litre wildlife pond is about 30 litres per hour before the margin. A 5,000 litre koi pond at the midpoint of 300 is about 1,500 before the margin and before depth cuts what leaves the stone. The same tape-measure pond is two purchases. Koi Zone’s table is far higher. This page does not average it into Evolution Aqua’s band.

Which listing matches which pond

For planted wildlife or goldfish around 1,000–2,000 litres, start with the small-kit class. The Blagdon two-outlet kit is titled to 2,000 litres at 320 litres per hour, with hoses and stones, at £38.79 and 4.3 from 1,998 reviews. The Pontec set at £29.45 and 450 litres per hour has two stones and no litre figure. Both are a surplus on the ornamental sum, not a koi pump. For koi at several thousand litres, start at the Blagdon 1800: koi to 5,000 litres, or ponds to 10,000, at 1,800 litres per hour and £72.99. Hose and stones are extra. The 2400 at £89.99 is the 7,500 litre koi line. Install is on the setup guide.
Blagdon Blagdon Pond Oxygenator 1800

Testsieger

Blagdon Blagdon Pond Oxygenator 1800
8.3/10about £72.99
View offer

Outlets are not extra air

A ten-outlet fitting does not put 2,400 litres per hour through each stone. The flow is shared. Airflow splits across the outlets you open. Buying the 2400 so a goldfish pond can have ten stones multiplies furniture, not oxygen. Two stones on 320 or 450 litres per hour serve the 2,000 litre kit class. Six outlets on the 1800 spread 1,800 litres per hour. They do not create six pumps. Capping Blagdon outlets will not speed the others up.

Warm weather is not a bigger pump by itself

Goldfish gasping in a heatwave is a reason to get air on and to test the water. UK reviews of the small Blagdon kit describe more active fish in hot weather. That is not a koi load. The Environment Agency calls emergency aeration a refuge until conditions ease, not an ammonia treatment. If fish are dying, test oxygen, ammonia and pH. Hygger has no IP code and no review line, so it is not the outdoor koi pick. The small kit is the 1,000–2,000 litre wildlife class. The 1800 is koi to 5,000 litres.

Common questions

How much air does a koi pond need per 1,000 litres?
Evolution Aqua’s band is about 200–400 litres per hour per 1,000 litres of koi pond, plus 10–20%. At the midpoint, a 5,000 litre pond is about 1,500 litres per hour before depth losses. Koi Zone’s gallon table is much higher. This page does not blend the two. Read the koi litre line on the listing you are about to buy.
Does a wildlife pond need the same pump?
A planted wildlife or goldfish pond is on the ornamental band, about 15 litres per hour per 1,000 litres. A 2,000 litre pond is about 30 litres per hour before the margin, so a 320 litre-per-hour kit is a different kind of surplus. It is not the same purchase as a pump titled for koi up to 5,000 litres.
Is 320 litres per hour enough for koi?
On Evolution Aqua’s koi band, 320 litres per hour is a small volume before depth takes more away. The Blagdon kit that delivers it is titled for standard ponds up to 2,000 litres, not the 5,000 litre koi line on the 1800. If the fish are koi at several thousand litres, start at 1,800 litres per hour in this set.
The title says 10,000 litres and also 5,000 litres for koi. Which number do I use?
Use the koi number when you keep koi, and the larger number for a more lightly stocked fish pond. On the 1800 that is 5,000 litres of koi or 10,000 litres of pond. On the 2400 it is 7,500 litres of koi or 15,000 litres of pond. The two figures are a stocking split, not a range you can average.
Will more outlets give each stone the full flow?
No. The litres per hour on the title are the pump’s total, shared across the outlets you open. Ten outlets on the 2400 do not mean ten times 2,400 litres per hour. Open the outlets you need, and expect a deep stone to show less air than the box suggested.
My goldfish were gasping in a heatwave. Is the small kit the same purchase as a koi pump?
Get air on, and test the water. A small kit can help a modest goldfish pond, which is what some UK reviews of the Blagdon kit describe. That is not evidence the same kit matches a koi load, and air is not an ammonia treatment. The koi purchase in this set remains the 1,800 litre-per-hour class.

Related pages

Pond air pump winter

Pond air pump

Best pond air pump: standard, value, and koi ponds

Pond air pump buying guide: check depth and the kit

How to install a pond air pump on an outdoor supply

Sources

Public UK and maker sources used for this page in October 2026. Prices, stars and review counts are from the eight amazon.co.uk listings captured on 20 October 2026. A splash rating, a litre band and a waterproof line are listing or maker claims, not a laboratory result.

  1. Evolution Aqua pond air pump calculator (retrieved 20 October 2026)
  2. Evolution Aqua air pump specifications (retrieved 20 October 2026)
  3. That Pond Guy, choosing koi pond equipment (retrieved 20 October 2026)
  4. Blagdon oxygenator kit manual (retrieved 20 October 2026)
  5. Approved Document P, electrical safety in dwellings (retrieved 20 October 2026)
  6. HSE, electrical equipment in damp places (retrieved 20 October 2026)
  7. Environment Agency, stillwater aeration (retrieved 20 October 2026)
  8. Met Office, winter water safety (retrieved 20 October 2026)