Can Gold Nugget Pleco (L018) and Japanese Ricefish (Medaka) Live Together?

Gold Nugget Pleco (L018) is a moderately assertive species (6/10), while Japanese Ricefish (Medaka) is peaceful (2/10). This notable difference means Gold Nugget Pleco (L018) may occasionally assert dominance over Japanese Ricefish (Medaka).

In terms of spatial distribution, Gold Nugget Pleco (L018) prefers the Bottom (Substrate) zone, 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.

Additional behavioural considerations to keep in mind: Hyperactive swimmers can stress shy, slow-moving species through constant motion.

Worth noting: Japanese Ricefish (Medaka) is a known jumper, so a tight-fitting lid is essential.

To improve the chances of a peaceful coexistence in this community tank: Provide a significantly larger tank (at least 50% more volume than the minimum) to allow both Gold Nugget Pleco (L018) and Japanese Ricefish (Medaka) to establish separate territories. Add plenty of line-of-sight breaks using driftwood, rocks, and dense planting to reduce territorial confrontations. A larger aquarium with ample hiding spots can help diffuse aggression and give the less dominant fish space to retreat.

The safe temperature window for both species falls between 27°C and 28°C. Aim for the midpoint of this range (around 27.5°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 5–12 dGH. Regular testing will ensure conditions stay within this range. An aquarium test kit is recommended for monitoring.

To house Gold Nugget Pleco (L018) and Japanese Ricefish (Medaka) together, plan for an aquarium of at least 300 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.

Because this pairing requires extra vigilance, include plenty of hiding spots — caves, driftwood, and dense plant clusters — so the less dominant fish can retreat when needed.

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

Gold Nugget Pleco (L018) prefers High (River/Stream) flow while Japanese Ricefish (Medaka) needs Low (Still Water) flow. Consider positioning filter outlets and using baffles to create zones of different current intensity within the same tank.