Can Lake Eacham Rainbowfish and Largereye Lampeye Killifish Live Together?

Lake Eacham Rainbowfish is a peaceful species (2/10), while Largereye Lampeye Killifish is peaceful (1/10). This modest difference means Lake Eacham Rainbowfish may occasionally assert dominance over Largereye Lampeye Killifish.

Lake Eacham Rainbowfish and Largereye Lampeye Killifish both frequent the Top (Surface) and 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.

Additional behavioural considerations to keep in mind: Hyperactive swimmers can stress shy, slow-moving species through constant motion. Aggressive eaters may outcompete shy fish for food, leading to malnutrition.

Worth noting: Lake Eacham Rainbowfish 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.

The safe temperature window for both species falls between 23°C and 27°C. Aim for the midpoint of this range (around 25.0°C) for optimal comfort.

Both fish can tolerate a pH between 6.8 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 Lake Eacham Rainbowfish and Largereye Lampeye Killifish together, plan for an aquarium of at least 110 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: Plants - lighly covered, Plants - Densely covered, Plants - Floating. 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.

This pairing usually fails when the tank is treated like a standard mixed community and the caution flags are ignored. Lake Eacham Rainbowfish and Largereye Lampeye 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.

Feeding time deserves special attention with this pairing. Lake Eacham Rainbowfish is an aggressive eater that may prevent Largereye Lampeye Killifish from getting enough food.

Because Lake Eacham Rainbowfish is a fast, competitive feeder, consider using sinking pellets or feeding at opposite ends of the setup to ensure Largereye Lampeye Killifish receives an adequate share.