Comment protéger un Patio Pond en hiver ? Le guide complet pour des Medakas en pleine forme ❄️🐟

Patio ponds, also known as Patio Ponds, are increasingly appealing to garden enthusiasts. Aesthetic, easy to install, and perfect for housing a few Medakas, minnows, or Notropis, these micro-ponds allow you to enjoy a true little ecosystem, even on a patio or balcony.

Whether you wish to keep Medakas, minnows, Notropis chrosomus, a few freshwater shrimp, or simply create a small corner of nature, a 190-liter pond is an excellent solution.

But one question comes up every winter:

Should you protect your Patio Pond against frost?

The answer is yes, especially if your fish are spending the winter outdoors. You must maintain constant gas exchange to ensure the survival of your fish.

Are Medakas cold-hardy?

Good news: Medakas (Oryzias latipes) are among the most cold-resistant ornamental fish. They can overwinter outside without any problem, provided their environment remains healthy.

The real danger is not so much the cold...

👉 It is the surface freezing over completely.

When the pond is completely covered in ice:

gas exchange is blocked;
carbon dioxide and gases from the decomposition of organic matter accumulate;
oxygen can no longer enter the water.

Even though Medakas significantly slow their activity during winter, they still need oxygenated water.

The Medaka (Oryzias latipes) is one of the most cold-resistant ornamental fish. Native to Japan, it handles the winters of Belgium and France without difficulty.

The same applies to several species adapted to small ponds, such as:

minnows;
Notropis chrosomus;
certain selected small goldfish;
several species of freshwater shrimp.

Provided, of course, that their pond is properly maintained. Contrary to popular belief, it is not the cold that represents the greatest danger. The real problem is the lack of oxygen caused by the surface freezing over completely.

Why do above-ground ponds freeze faster?

Unlike an in-ground pond, a Patio Pond is exposed to the cold on all sides.

Consequences:

the water cools much faster;
a layer of ice can form from the very first freezing nights;
during prolonged cold spells, the ice can become very thick.

The 190-liter ponds remain perfectly suited for Medakas, but they require a bit more vigilance during winter.

Why can ice become dangerous?

When the entire surface is covered in ice:

oxygen can no longer enter the water;
carbon dioxide gradually accumulates;
gases from the decomposition of dead leaves and sediment remain trapped in the pond.

Even though Medakas enter a winter resting period and significantly reduce their activity, they continue to breathe.

Without gas exchange, the environment can quickly become unfavorable for their survival.

Never break the ice

This is a very common mistake. Many owners think they are doing the right thing by breaking the ice with a hammer or a heavy object.

In reality, the vibrations propagate through all the water and can cause significant stress to the fish, sometimes even internal injuries. If your pond is frozen, it is better to prevent the ice from forming rather than trying to break it.

An in-ground pond naturally benefits from the soil's thermal inertia. Conversely, a Patio Pond is exposed to the cold on all its sides.

Result:

the water cools much faster;
a layer of ice appears from the first freezing nights;
during long periods of cold, the ice can become particularly thick.

The 190-liter models, like the one offered by Aquishop, remain perfectly suited for Medakas, but simply require appropriate winter protection.

The solution: an intelligent floating heater

For small ponds and Patio Ponds, we recommend the OASE IceFree Thermo 330. Unlike a simple anti-freeze float, this model includes a 330 W heating element that is automatically controlled.

Its main advantages:

maintains an opening in the ice down to approximately -20 °C;
starts automatically only when a risk of freezing is detected;
maintains essential gas exchange for the fish;
better water oxygenation;
operation is particularly suited to shallow ponds and small volumes like Patio Ponds.

In other words, the device does not try to heat the entire pond.

It simply maintains an ice-free zone, exactly what your fish need to get through the winter in good conditions.

Some additional advice

To maximize the chances of success:

regularly remove dead leaves before winter;
limit feeding when the temperature drops below 10 °C;
avoid moving fish during the cold period;
leave aquatic plants in place if they are hardy;
simply monitor that the opening in the ice remains clear.

A small investment for great peace of mind

A Patio Pond represents a true little ecosystem. A few Medakas, some plants, and a bit of filtration are enough to create a living pond all year round.

By adding a suitable anti-freeze system like the OASE IceFree Thermo 330, you easily secure your fish's overwintering without having to intervene at every freeze episode.

If you only remember one thing:

Medakas are surprisingly robust fish, but they still need a minimum of gas exchange during winter.

If you own a 190-liter Patio Pond, a floating heater like the IceFree Thermo 330 is a simple, reliable, and economical solution to get through the winter with complete peace of mind. Your fish will thank you... as soon as the first warm days arrive, when they resume their activity at the surface.

Our Aquiflor tips for successfully overwintering a Patio Pond

After over 30 years of experience in garden ponds, we also recommend:

✅ removing dead leaves before winter to limit fermentation gas production;

✅ gradually stopping feeding when the water drops below 8 to 10 °C;

✅ leaving hardy aquatic plants in place; they will naturally contribute to the pond's balance in the spring;

✅ regularly checking that the filtration is adapted to winter temperatures;

✅ checking that the opening created by the anti-freeze system remains clear.

These few actions are generally enough to get through the winter without any unpleasant surprises.

What equipment is needed to protect a 190-liter Patio Pond?

If you own a 190-liter above-ground pond, we recommend the following combination:

an OASE IceFree Thermo 330 anti-freeze system;
a few hardy aquatic plants;
light, adapted filtration;
a reasonable population of Medakas or small fish.

This combination offers excellent biological balance throughout the year. Medakas, minnows, and Notropis are perfectly capable of spending the winter outside. What they fear above all is not the cold, but the lack of gas exchange when the pond freezes over completely.

By equipping your Patio Pond with a floating heater like the OASE IceFree Thermo 330, you sustainably protect your fish, preserve the biological balance of your pond, and enjoy a living water feature from the very first beautiful days of spring.