Can Cuckoo Catfish and Japanese Ricefish (Medaka) Live Together?

🟢Ideal Tank Mates

Yes, Cuckoo Catfish and Japanese Ricefish (Medaka) are ideal tank mates. Both species share compatible water parameters and peaceful temperaments, making them well-suited for a community aquarium. They occupy different areas of the water column, which reduces competition for space. A minimum tank size of 408 litres is recommended.


At a Glance

Cuckoo Catfish

Synodontis multipunctatus

Japanese Ricefish (Medaka)

Oryzias latipes

🐠Family Group
Cuckoo Catfish
Catfish
Japanese Ricefish (Medaka)
Killifish
Temperament
Cuckoo Catfish
Semi-Aggressive (5/10)
Japanese Ricefish (Medaka)
Peaceful (2/10)
Temperature
✓ Compatible
Cuckoo Catfish
24–28°C
Japanese Ricefish (Medaka)
10–28°C
pH Range
✓ Compatible
Cuckoo Catfish
7.5–9
Japanese Ricefish (Medaka)
6.5–8.5
Hardness (dGH)
✓ Compatible
Cuckoo Catfish
10–25
Japanese Ricefish (Medaka)
5–25
Water Type
✓ Compatible
Cuckoo Catfish
Freshwater Only
Japanese Ricefish (Medaka)
Brackish Tolerant
Flow Preference
✓ Compatible
Cuckoo Catfish
Moderate
Japanese Ricefish (Medaka)
Low
Min Tank Volume
Combined: 408 L
Cuckoo Catfish
340 L
Japanese Ricefish (Medaka)
19 L
Swimming Level
✓ Different zones
Cuckoo Catfish
MiddleBottom
Japanese Ricefish (Medaka)
Top
🏷️Behavior Tags
Cuckoo Catfish
Hyperactive / Fast SwimmerNocturnalFry PredatorDigger (Disturbs Substrate)
Japanese Ricefish (Medaka)
Nano / Bite-sized (Predation Risk)Hyperactive / Fast SwimmerJumper (Lid Required)Fry Predator

Behaviour & Temperament

Cuckoo Catfish is a moderately assertive species (5/10), while Japanese Ricefish (Medaka) is peaceful (2/10). This modest difference means Cuckoo Catfish may occasionally assert dominance over Japanese Ricefish (Medaka).

In terms of spatial distribution, Cuckoo Catfish prefers the Middle (Open Water) and Bottom (Substrate) zones, whereas Japanese Ricefish (Medaka) occupies the Top (Surface) zone. Because they use different levels of the water column, territorial disputes are less likely and the tank will appear more balanced.

Worth noting: Cuckoo Catfish is nocturnal and will be most active after lights-out, naturally reducing daytime encounters. Also, Japanese Ricefish (Medaka) is a known jumper, so a tight-fitting lid is essential.

Water Parameters

The safe temperature window for both species falls between 24°C and 28°C. Aim for the midpoint of this range (around 26.0°C) for optimal comfort.

Both fish can tolerate a pH between 7.5 and 8.5. Maintaining a stable value within this band is more important than hitting an exact number.

For general hardness, the shared comfort zone is 10–25 dGH. Regular testing will ensure conditions stay within this range. An aquarium test kit is recommended for monitoring.

Tank Setup

To house Cuckoo Catfish and Japanese Ricefish (Medaka) together, plan for an aquarium of at least 408 litres with a minimum length of 120 cm. This accounts for the larger species' space requirements with an additional 20 % buffer to reduce territorial tension.

Providing a mix of open swimming space and sheltered areas with rocks, driftwood, or plants will keep both species comfortable and allow natural behaviour.

Specific environmental needs for this combination include: Sand (Sifters), Smooth Gravel (Sensitive Barbels), Driftwood (Digestion/Hiding), Plants - Densely covered, Plants - Floating. Meeting these requirements will help both species thrive.

Both species do well with moderate (standard) water movement, so a standard filtration setup rated for the tank volume should suffice.

Find the right tank equipment

Browse tanks, décor, and equipment suited for this setup.

Frequently Asked Questions

Can Cuckoo Catfish and Japanese Ricefish (Medaka) live together?

Yes. Cuckoo Catfish and Japanese Ricefish (Medaka) are considered ideal tank mates. Their water parameters, temperaments, and behaviour profiles are well matched for a community aquarium.

What size tank do Cuckoo Catfish and Japanese Ricefish (Medaka) need?

A minimum of 408 litres (tank length at least 120 cm) is recommended. This provides enough space for both species to establish their own areas and reduces the likelihood of territorial disputes.

What water temperature is best for Cuckoo Catfish and Japanese Ricefish (Medaka) together?

Keep the aquarium between 24°C and 28°C. A target of around 26.0°C sits comfortably within both species' preferred ranges.

Are Cuckoo Catfish or Japanese Ricefish (Medaka) aggressive?

Cuckoo Catfish is moderately assertive (5/10) and Japanese Ricefish (Medaka) is peaceful (2/10). Their similar temperaments generally lead to a peaceful coexistence.

What pH do Cuckoo Catfish and Japanese Ricefish (Medaka) need?

Both species overlap in the 7.5–8.5 pH range. Consistency is key — avoid sudden swings, and test regularly to stay within this window.

Does Cuckoo Catfish being nocturnal affect compatibility?

Cuckoo Catfish is most active after lights-out, which naturally reduces daytime encounters with its tank mate. This can actually be beneficial, as both fish get undisturbed time to feed and explore. Just ensure food reaches Cuckoo Catfish during evening hours.


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