Can Bucktooth Tetra (Exodon) and Molly (Sailfin/Black/Dalmatian) Live Together?

Bucktooth Tetra (Exodon) is a highly aggressive species (9/10), while Molly (Sailfin/Black/Dalmatian) is generally mild-mannered (3/10). This notable difference means Bucktooth Tetra (Exodon) may occasionally assert dominance over Molly (Sailfin/Black/Dalmatian).

Large aggression gap (6 points) between Bucktooth Tetra (Exodon) and Molly (Sailfin/Black/Dalmatian) increases stress risk for the more peaceful fish.

Bucktooth Tetra (Exodon) and Molly (Sailfin/Black/Dalmatian) both frequent the Middle (Open Water) and Top (Surface) 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: Bucktooth Tetra (Exodon) is a known jumper, so a tight-fitting lid is essential.

To improve the chances of a peaceful coexistence in this community tank: A larger aquarium with ample hiding spots can help diffuse aggression and give the less dominant fish space to retreat. Keep fin nippers in larger groups to distribute nipping behaviour among conspecifics rather than tank mates.

The safe temperature window for both species falls between 24°C and 28°C. Aim for the midpoint of this range (around 26.0°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 12–15 dGH. Regular testing will ensure conditions stay within this range.

To house Bucktooth Tetra (Exodon) and Molly (Sailfin/Black/Dalmatian) together, plan for an aquarium of at least 240 litres with a minimum length of 120 cm. This accounts for the larger species' space requirements with an additional 20 % buffer to reduce territorial tension.

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: Driftwood (Digestion/Hiding), 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.