Can Festivum and Golden Wonder Killifish Live Together?

Festivum is a generally mild-mannered species (4/10), while Golden Wonder Killifish is moderately assertive (6/10). This modest difference means Golden Wonder Killifish may occasionally assert dominance over Festivum.

Festivum and Golden Wonder Killifish both frequent the 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: Festivum 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 Festivum and Golden Wonder Killifish 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 28°C. Aim for the midpoint of this range (around 26.0°C) for optimal comfort.

Both fish can tolerate a pH between 6 and 7.2. Maintaining a stable value within this band is more important than hitting an exact number.

For general hardness, the shared comfort zone is 5–12 dGH. Regular testing will ensure conditions stay within this range.

To house Festivum and Golden Wonder Killifish together, plan for an aquarium of at least 150 litres with a minimum length of 90 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: Driftwood (Digestion/Hiding), Plants - Floating. 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.

This pairing usually fails when the tank is treated like a standard mixed community and the caution flags are ignored. Festivum and Golden Wonder Killifish 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.