Can Blue Dolphin (Hap) and Red Head Tapajos (Geophagus) Live Together?

Blue Dolphin (Hap) is a moderately assertive species (5/10), while Red Head Tapajos (Geophagus) is generally mild-mannered (4/10). This modest difference means Blue Dolphin (Hap) may occasionally assert dominance over Red Head Tapajos (Geophagus).

Blue Dolphin (Hap) and Red Head Tapajos (Geophagus) both frequent the Middle (Open Water) and 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 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.

For general hardness, the shared comfort zone is 10–10 dGH. Regular testing will ensure conditions stay within this range.

To house Blue Dolphin (Hap) and Red Head Tapajos (Geophagus) together, plan for an aquarium of at least 570 litres with a minimum length of 150 cm. This accounts for the larger species' space requirements with an additional 20 % buffer to reduce territorial tension.

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), Smooth Gravel (Sensitive Barbels), Driftwood (Digestion/Hiding). 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.