Can Clown Pleco (L104) and Golden Wonder Killifish Live Together?

Clown Pleco (L104) is a generally mild-mannered species (3/10), while Golden Wonder Killifish is moderately assertive (6/10). This modest difference means Golden Wonder Killifish may occasionally assert dominance over Clown Pleco (L104).

In terms of spatial distribution, Clown Pleco (L104) prefers the Bottom (Substrate) zone, whereas Golden Wonder Killifish 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: Clown Pleco (L104) is nocturnal and will be most active after lights-out, naturally reducing daytime encounters. Also, Golden Wonder Killifish 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 Clown Pleco (L104) and Golden Wonder Killifish 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 23°C and 28°C. Aim for the midpoint of this range (around 25.5°C) for optimal comfort.

Both fish can tolerate a pH between 6 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.

To house Clown Pleco (L104) and Golden Wonder Killifish together, plan for an aquarium of at least 90 litres with a minimum length of 60 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), 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.