Can Red-Tail Catfish and Three Spot Gourami (Blue/Gold/Opaline) Live Together?

Red-Tail Catfish is a semi-aggressive species (7/10), while Three Spot Gourami (Blue/Gold/Opaline) is moderately assertive (6/10). This modest difference means Red-Tail Catfish may occasionally assert dominance over Three Spot Gourami (Blue/Gold/Opaline).

In terms of spatial distribution, Red-Tail Catfish prefers the Bottom (Substrate) zone, whereas Three Spot Gourami (Blue/Gold/Opaline) occupies the Top (Surface) and Middle (Open Water) zones. Because they use different levels of the water column, territorial disputes are less likely and the tank will appear more balanced.

Worth noting: Red-Tail Catfish is nocturnal and will be most active after lights-out, naturally reducing daytime encounters.

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 Red-Tail Catfish and Three Spot Gourami (Blue/Gold/Opaline) to establish separate territories. Add plenty of line-of-sight breaks using driftwood, rocks, and dense planting to reduce territorial confrontations. Keep fin nippers in larger groups to distribute nipping behaviour among conspecifics rather than tank mates.

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 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 Red-Tail Catfish and Three Spot Gourami (Blue/Gold/Opaline) together, plan for an aquarium of at least 4560 litres with a minimum length of 300 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: Sand (Sifters), Smooth Gravel (Sensitive Barbels), Driftwood (Digestion/Hiding), Plants - Densely covered, Plants - Floating. Meeting these requirements will help both species thrive.

Note a potential conflict in setup requirements: Red-Tail Catfish is a plant destroyer, which conflicts with Three Spot Gourami (Blue/Gold/Opaline)'s requirement for live plants. Compromise where possible or prioritise the more critical need.

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