Can Geophagus Orange Head Tapajos and Molly (Sailfin/Black/Dalmatian) Live Together?

Both Geophagus Orange Head Tapajos and Molly (Sailfin/Black/Dalmatian) are generally mild-mannered species with an aggression score of 3/10. Their matching temperaments mean neither fish is likely to dominate the other in a shared aquarium.

Geophagus Orange Head Tapajos and Molly (Sailfin/Black/Dalmatian) 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.

The safe temperature window for both species falls between 26°C and 28°C. Aim for the midpoint of this range (around 27.0°C) for optimal comfort.

Both fish can tolerate a pH between 7.5 and 7.5. Maintaining a stable value within this band is more important than hitting an exact number.

Hardness requirements are incompatible: Geophagus Orange Head Tapajos needs 1–10 dGH while Molly (Sailfin/Black/Dalmatian) requires 12–30 dGH.

To house Geophagus Orange Head Tapajos and Molly (Sailfin/Black/Dalmatian) together, plan for an aquarium of at least 280 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), Smooth Gravel (Sensitive Barbels), Plants - Densely covered, Established Algae (Otocinclus). 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.

Geophagus Orange Head Tapajos and Molly (Sailfin/Black/Dalmatian) 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.