Can Altum Angel and Florida Flagfish Live Together?

Both Altum Angel and Florida Flagfish are moderately assertive species with an aggression score of 5/10. Their matching temperaments mean neither fish is likely to dominate the other in a shared aquarium.

Altum Angel and Florida Flagfish 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. Two territorial species may clash over territory, especially in smaller tanks.

There is no temperature overlap between Altum Angel (27–32°C) and Florida Flagfish (18–26°C). This fundamental mismatch makes long-term cohabitation impractical.

Both fish can tolerate a pH between 6.5 and 6.5. Maintaining a stable value within this band is more important than hitting an exact number.

Hardness requirements are incompatible: Altum Angel needs 1–5 dGH while Florida Flagfish requires 10–25 dGH.

To house Altum Angel and Florida Flagfish 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, Established Algae (Otocinclus), 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 Florida Flagfish 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.