Can Delhezi Bichir (Armored Bichir) and Harlequin Shark Live Together?

Delhezi Bichir (Armored Bichir) is a moderately assertive species (6/10), while Harlequin Shark is semi-aggressive (8/10). This modest difference means Harlequin Shark may occasionally assert dominance over Delhezi Bichir (Armored Bichir).

Delhezi Bichir (Armored Bichir) and Harlequin Shark 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.

Worth noting: Delhezi Bichir (Armored Bichir) is nocturnal and will be most active after lights-out, naturally reducing daytime encounters. Also, Delhezi Bichir (Armored Bichir) is a known jumper, so a tight-fitting lid is essential.

To improve the chances of a peaceful coexistence in this community tank: Provide a significantly larger tank (at least 50% more volume than the minimum) to allow both Delhezi Bichir (Armored Bichir) and Harlequin Shark to establish separate territories. Add plenty of line-of-sight breaks using driftwood, rocks, and dense planting to reduce territorial confrontations.

The safe temperature window for both species falls between 24°C and 27°C. Aim for the midpoint of this range (around 25.5°C) for optimal comfort.

Both fish can tolerate a pH between 6 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 5–15 dGH. Regular testing will ensure conditions stay within this range.

To house Delhezi Bichir (Armored Bichir) and Harlequin Shark 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.

Because this pairing requires extra vigilance, include plenty of hiding spots — caves, driftwood, and dense plant clusters — so the less dominant fish can retreat when needed.

Specific environmental needs for this combination include: Sand (Sifters), Smooth Gravel (Sensitive Barbels), Driftwood (Digestion/Hiding), Established Algae (Otocinclus). Meeting these requirements will help both species thrive.

Delhezi Bichir (Armored Bichir) prefers Low (Still Water) flow while Harlequin Shark needs High (River/Stream) flow. Consider positioning filter outlets and using baffles to create zones of different current intensity within the same tank.

This pairing usually fails when the tank is treated like a standard mixed community and the caution flags are ignored. Delhezi Bichir (Armored Bichir) and Harlequin Shark need extra room, more cover, and closer observation during the first few weeks so small aggression, feeding, or territory issues do not snowball into a long-term problem.