Can Japanese Ricefish (Medaka) and Royal Pleco (L190) Live Together?
Yes, Japanese Ricefish (Medaka) and Royal Pleco (L190) 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 540 litres is recommended.
At a Glance
Behaviour & Temperament
Japanese Ricefish (Medaka) is a peaceful species (2/10), while Royal Pleco (L190) is moderately assertive (5/10). This modest difference means Royal Pleco (L190) may occasionally assert dominance over Japanese Ricefish (Medaka).
In terms of spatial distribution, Japanese Ricefish (Medaka) prefers the Top (Surface) zone, whereas Royal Pleco (L190) occupies the Bottom (Substrate) zone. Because they use different levels of the water column, territorial disputes are less likely and the tank will appear more balanced.
Worth noting: Royal Pleco (L190) 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 22°C and 28°C. Aim for the midpoint of this range (around 25.0°C) for optimal comfort.
Both fish can tolerate a pH between 6.5 and 7.5. Maintaining a stable value within this band is more important than hitting an exact number.
For general hardness, the shared comfort zone is 5–15 dGH. Regular testing will ensure conditions stay within this range. An aquarium test kit is recommended for monitoring.
Tank Setup
To house Japanese Ricefish (Medaka) and Royal Pleco (L190) together, plan for an aquarium of at least 540 litres with a minimum length of 150 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: Plants - Densely covered, Plants - Floating, Driftwood (Digestion/Hiding). Meeting these requirements will help both species thrive.
Note a potential conflict in setup requirements: Royal Pleco (L190) is a plant destroyer, which conflicts with Japanese Ricefish (Medaka)'s requirement for live plants. Compromise where possible or prioritise the more critical need.
Japanese Ricefish (Medaka) prefers Low (Still Water) flow while Royal Pleco (L190) needs High (River/Stream) flow. Consider positioning filter outlets and using baffles to create zones of different current intensity within the same tank.
Find the right tank equipment
Browse tanks, décor, and equipment suited for this setup.
Frequently Asked Questions
Can Japanese Ricefish (Medaka) and Royal Pleco (L190) live together?▾
Yes. Japanese Ricefish (Medaka) and Royal Pleco (L190) are considered ideal tank mates. Their water parameters, temperaments, and behaviour profiles are well matched for a community aquarium.
What size tank do Japanese Ricefish (Medaka) and Royal Pleco (L190) need?▾
A minimum of 540 litres (tank length at least 150 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 Japanese Ricefish (Medaka) and Royal Pleco (L190) together?▾
Keep the aquarium between 22°C and 28°C. A target of around 25.0°C sits comfortably within both species' preferred ranges.
Are Japanese Ricefish (Medaka) or Royal Pleco (L190) aggressive?▾
Japanese Ricefish (Medaka) is peaceful (2/10) and Royal Pleco (L190) is moderately assertive (5/10). Their similar temperaments generally lead to a peaceful coexistence.
What pH do Japanese Ricefish (Medaka) and Royal Pleco (L190) need?▾
Both species overlap in the 6.5–7.5 pH range. Consistency is key — avoid sudden swings, and test regularly to stay within this window.
How do I manage Royal Pleco (L190)'s territorial behaviour?▾
Provide line-of-sight breaks using rocks, driftwood, and dense planting. A larger tank gives Royal Pleco (L190) space to claim a territory without encroaching on the other fish's area. Adding décor that divides the tank into distinct zones works especially well.
Does Royal Pleco (L190) being nocturnal affect compatibility?▾
Royal Pleco (L190) 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 Royal Pleco (L190) during evening hours.
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