Keeping Medaka outdoors: bowl or pond?

In Japan, keeping Medaka outdoors in a bowl - the traditional 'Medaka Bowl' - is an age-old custom. This way of keeping them is also gaining ground in the Netherlands. But what suits your situation better: a bowl or a pond?

Why Medaka are so suitable for outdoor keeping

Medaka are remarkably hardy for their size. They tolerate water temperatures from near freezing to over 28°C, and can even survive the Dutch winter in a well-designed outdoor setup - provided the water does not completely freeze over and there is sufficient depth.

The Medaka Bowl: the traditional Japanese approach

A Medaka Bowl is a stylish, filterless bowl - often placed on a terrace, balcony, or patio. The idea is minimalistic: no filter, no heating, just a stable, small water garden with Medaka, some floating plants, and possibly a stone or two.

Advantages of a bowl:

• Compact - also fits on a small balcony or terrace
• Decorative and atmospheric, a real statement piece
• Low maintenance due to the absence of technology

Points of attention:

• Without a filter, the biological balance is more fragile - use Medaka Care or Medaka PSB to naturally break down organic waste
• Protect the bowl with a cover net against birds, who love Medaka as a snack
• A small amount of water heats up and cools down faster than a pond - keep a close eye on the bowl during extreme heat or frost

Medaka in a (mini)pond

Do you already have a pond, or are you considering one? Medaka are also a good choice for ponds, especially in combination with other calm pond inhabitants.

Advantages of a pond:

• Larger water volume means more stable water quality and temperature
• More space for a larger group of Medaka
• Overwintering is often more straightforward due to the larger buffer

Points of attention:

• Provide sufficient shelter (floating plants, shallow and deeper zones) against herons and other predators
• Do not combine with larger, predatory pond fish that see Medaka as prey
• Again, in extreme frost, a section that does not completely freeze over is important for survival

Overwintering: what to look out for

Whether you choose a bowl or a pond, for winter:

• Ensure sufficient depth (for a pond, at least 40-60 cm) so that the water does not freeze completely
• Medaka become inactive and barely eat at low temperatures - stop feeding then, as this unnecessarily burdens the water
• A small bowl is more vulnerable to freezing solid than a pond - consider temporarily bringing the bowl indoors during severe frost or insulating it extra

What suits you?

• Small balcony or terrace, looking for a decorative element? Choose the Medaka Bowl
• Already have a pond, or space for a larger group? Medaka fit perfectly in a calm pond environment
• Doubting the hardiness in your situation? Feel free to visit for personal advice

Questions about setting up your outdoor Medaka setup? Visit our store in Heinkenszand, or ask your question via chat.