Can Least Killifish (Heterandria) and Sparkling Gourami Live Together?

Least Killifish (Heterandria) is a peaceful species (1/10), while Sparkling Gourami is generally mild-mannered (3/10). This modest difference means Sparkling Gourami may occasionally assert dominance over Least Killifish (Heterandria).

Least Killifish (Heterandria) and Sparkling Gourami both frequent the Top (Surface), Middle (Open Water), and 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.

Additional behavioural considerations to keep in mind: Hyperactive swimmers can stress shy, slow-moving species through constant motion. Shrimp eaters may also prey on very small nano fish.

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 22°C and 27°C. Aim for the midpoint of this range (around 24.5°C) for optimal comfort.

Both fish can tolerate a pH between 7 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 5–18 dGH. Regular testing will ensure conditions stay within this range. An aquarium test kit is recommended for monitoring.

To house Least Killifish (Heterandria) and Sparkling Gourami together, plan for an aquarium of at least 46 litres with a minimum length of 45 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: Plants - Densely covered, Plants - Floating, Leaf Litter/Blackwater. 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.

Feeding time deserves special attention with this pairing. Sparkling Gourami is a known shrimp eater and may prey on small invertebrates or nano fish like Least Killifish (Heterandria).