Can Dwarf Pea Puffer and Rachov's Killifish (Annual) Live Together?

Dwarf Pea Puffer is a semi-aggressive species (8/10), while Rachov's Killifish (Annual) is generally mild-mannered (3/10). This notable difference means Dwarf Pea Puffer may occasionally assert dominance over Rachov's Killifish (Annual).

Dwarf Pea Puffer and Rachov's Killifish (Annual) both frequent the 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: Shrimp eaters may also prey on very small nano fish.

Worth noting: Rachov's Killifish (Annual) 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 Dwarf Pea Puffer and Rachov's Killifish (Annual) to establish separate territories. Add plenty of line-of-sight breaks using driftwood, rocks, and dense planting to reduce territorial confrontations. 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 22°C and 26°C. Aim for the midpoint of this range (around 24.0°C) for optimal comfort.

Both fish can tolerate a pH between 6.5 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 4–12 dGH. Regular testing will ensure conditions stay within this range. An aquarium test kit is recommended for monitoring.

To house Dwarf Pea Puffer and Rachov's Killifish (Annual) together, plan for an aquarium of at least 72 litres with a minimum length of 60 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, Sand (Sifters), Soil / Nutrient Rich, Leaf Litter/Blackwater. Meeting these requirements will help both species thrive.

Note a potential conflict in setup requirements: Dwarf Pea Puffer requires Sand (Sifters), while Rachov's Killifish (Annual) requires Soil / Nutrient Rich. These substrate types may be difficult to provide simultaneously. Compromise where possible or prioritise the more critical need.

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. Dwarf Pea Puffer is a known shrimp eater and may prey on small invertebrates or nano fish like Rachov's Killifish (Annual).