Can Black Ocellatus and Brilliant Rummy-Nose Tetra Live Together?

Black Ocellatus is a semi-aggressive species (7/10), while Brilliant Rummy-Nose Tetra is peaceful (1/10). This notable difference means Black Ocellatus may occasionally assert dominance over Brilliant Rummy-Nose Tetra.

Large aggression gap (6 points) between Black Ocellatus and Brilliant Rummy-Nose Tetra increases stress risk for the more peaceful fish.

Black Ocellatus and Brilliant Rummy-Nose Tetra both frequent the Bottom (Substrate) region of the setup. This overlap can increase competition for space, so providing ample room and cover is important to keep both species comfortable.

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.

The pH requirements of Black Ocellatus (7.5–9) and Brilliant Rummy-Nose Tetra (5–7) do not overlap, making it impossible to satisfy both species simultaneously.

For general hardness, the shared comfort zone is 8–8 dGH. Regular testing will ensure conditions stay within this range.

To house Black Ocellatus and Brilliant Rummy-Nose Tetra together, plan for an aquarium of at least 75 litres with a minimum length of 60 cm. This recommendation combines the stricter species minimums with a community-load allowance so the pairing has realistic long-term space and filtration headroom.

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), Shells (Breeding/Hiding), Plants - Densely covered, Leaf Litter/Blackwater. Meeting these requirements will help both species thrive.

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

Black Ocellatus and Brilliant Rummy-Nose Tetra are the kind of pair that can look acceptable in a shop but become a maintenance problem at home. The main risk is not a single number in the chart; it is the way incompatible behavior, water needs, or pressure on space compounds over time once both fish are established in the same tank.