Can Blue Dolphin (Hap) and Clown Killifish Live Together?

Blue Dolphin (Hap) is a moderately assertive species (5/10), while Clown Killifish is peaceful (2/10). This modest difference means Blue Dolphin (Hap) may occasionally assert dominance over Clown Killifish.

In terms of spatial distribution, Blue Dolphin (Hap) prefers the Middle (Open Water) and Bottom (Substrate) zones, whereas Clown Killifish occupies the Top (Surface) zone. Because they use different levels of the water column, territorial disputes are less likely and the tank will appear more balanced.

Additional behavioural considerations to keep in mind: Hyperactive swimmers can stress shy, slow-moving species through constant motion.

Worth noting: Clown Killifish is a known jumper, so a tight-fitting lid is essential.

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.

The pH requirements of Blue Dolphin (Hap) (7.5–8.6) and Clown Killifish (5–7) do not overlap, making it impossible to satisfy both species simultaneously.

Hardness requirements are incompatible: Blue Dolphin (Hap) needs 10–25 dGH while Clown Killifish requires 1–8 dGH. An aquarium test kit is recommended for monitoring.

To house Blue Dolphin (Hap) and Clown Killifish 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), Plants - Floating, Plants - Densely covered, Leaf Litter/Blackwater. 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.