The recommended depth for a Koi pond is about 1.5–2 meters (or 4–6 feet). This is the best environment for Koi measuring about 15–20 centimeters (or 6–8 inches). As you can see, big fish need a big pond.

The minimum depth you should consider is at least 1.3 meter. But the more fish you have, and the bigger they are, the deeper the pond should be.

And at the other end of the scale, the maximum recommended depth is about 2.5 meters – which is only really necessary for particularly vast ponds with lots of large Koi.

No, preferably not. This is for the deepest part of your pond, usually around 40% of its total area.

Ideally, a good Koi pond should have varying depths. Experts recommend a gradual slope, starting from about 1 meter at the shallowest point.

This way, you can easily create a range of different environments for your fish to enjoy. A pond with varying depths will have water with different temperatures, different levels of light, and of course a spread of different plants too.

Koi like a little variety where they swim, so this is a great way to encourage that natural behavior.

Of course, a big slope isn’t always possible with every pond, especially above-ground ponds. In that case, build your pond to the recommended depth for your Koi, and try creating a diverse environment for them to explore in other ways – by including things such as sheltered areas, a range of plants, or bubbles and waterfalls.

There are a few reasons why Koi need a nice, deep pond – and not just because they’re big fish. Some of those reasons are…

A deep Koi pond supports natural fish behavior. Koi like spending time in different depths of water and in a variety of environments – such as sheltered areas and under waterfalls – and a deep pond lets them do this.

A 1–2 meter deep pond is the perfect depth to keep the water at the right temperature for your Koi, and that’s the case for most climates and seasons. In the summer, a deep pond will keep the water cool enough; In freezing winters, there's a greater volume of relatively warm, 39-degree water at the bottom for them to overwinter under the ice

That said, if you live in a more extreme climate (somewhere very hot or cold year-round or with harsh seasons, for instance), you should seek advice from local experts on the best depth for a pond in your area.

Deeper ponds stay cooler, and cooler water can hold more oxygen than warm water. That’s great for your fish, as it means they’ll get the right amount of oxygen to stay happy and healthy.

Oase can help you build the perfect pond for your space – with all the high-tech equipment and expert know-how you need. Read our DIY pond guides and explore our outdoor pond products to learn more about creating the perfect Koi home.