Can Altum Angel and Ramu Rainbowfish Live Together?

Altum Angel is a moderately assertive species (5/10), while Ramu Rainbowfish is generally mild-mannered (3/10). This modest difference means Altum Angel may occasionally assert dominance over Ramu Rainbowfish.

Altum Angel and Ramu Rainbowfish both frequent the Middle (Open Water) region of the setup. This overlap can increase competition for space, so providing ample room and cover is important to keep both species comfortable.

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

Worth noting: Ramu Rainbowfish is a known jumper, so a tight-fitting lid is essential.

The safe temperature window for both species falls between 27°C and 29°C. Aim for the midpoint of this range (around 28.0°C) for optimal comfort.

The pH requirements of Altum Angel (4.5–6.5) and Ramu Rainbowfish (7–8) do not overlap, making it impossible to satisfy both species simultaneously.

For general hardness, the shared comfort zone is 5–5 dGH. Regular testing will ensure conditions stay within this range.

To house Altum Angel and Ramu Rainbowfish together, plan for an aquarium of at least 400 litres with a minimum length of 120 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), Driftwood (Digestion/Hiding), Leaf Litter/Blackwater, Plants - Floating, Smooth Gravel (Sensitive Barbels), Plants - Densely covered. 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.

Altum Angel and Ramu Rainbowfish 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.