Garden pond for goldfish: volume, equipment and budget
A garden pond for goldfish needs at least 1,000 litres and 80 cm of depth to get through winter outdoors safely. It’s the ideal habitat for a species that reaches 25-30 cm and lives 15 to 20 years: space, natural insects, real seasons. Realistic start-up budget: 400 to 1,200 € depending on the build you choose.
What volume and depth should you plan for?
Allow 1,000 litres for 4 to 5 goldfish, bearing in mind that they breed quickly. Depth is the safety factor: a zone at least 80 cm deep (100 cm in cold regions) stays frost-free and lets the fish overwinter there in slow motion. A pond under 500 litres freezes too hard and overheats in summer.
Liner, preformed shell or raised pond?
- EPDM liner (10 to 15 €/m²): the most flexible and most durable option (30 years and more), laid over a protective underlay.
- Preformed shell (150 to 400 € for 500 to 1,000 L): quick to install, but limited in shape and volume.
- Raised wooden pond kit (300 to 800 €): no digging, ideal on a terrace, but more exposed to frost.
What filtration for clear water?
A pump plus pressurized filter kit with built-in UV (150 to 400 € for 1,000 to 3,000 L) is the standard: the UV neutralizes green water, unavoidable in full sun, on the principle detailed in our article on UV sterilizers. Add marginal plants (iris, rushes) and oxygenators that soak up nitrates, produced by the same nitrogen cycle as in an aquarium.
How do you protect the fish?
The heron is enemy number one: a taut net (20 to 40 €) or deep banks with no convenient “steps” limit the damage. Also plan a shaded zone (water lilies) and, if young children use the garden, a rigid safety grid.
Frequently asked questions
Should goldfish be fed in winter?
No. Below 10 °C their metabolism almost stops: stop feeding entirely between November and March — they live off their reserves.
Can I move a goldfish from an aquarium to a pond?
Yes, it’s even the right thing to do — but in spring, once the pond water is above 15 °C, with slow temperature acclimatization.
Should the pump run all year round?
The filtration runs from April to October. In winter, switch it off or raise it near the surface so it doesn’t stir up the “warm” layer of water at the bottom.
This guide is part of Planète Pets’s Fishkeeping universe. Our advice is general in nature: for any health concern, your veterinarian remains the only reference.