Can Rachov's Killifish (Annual) and Violet Goby (Dragon Goby) Live Together?

Rachov's Killifish (Annual) is a generally mild-mannered species (3/10), while Violet Goby (Dragon Goby) is peaceful (2/10). This modest difference means Rachov's Killifish (Annual) may occasionally assert dominance over Violet Goby (Dragon Goby).

Rachov's Killifish (Annual) and Violet Goby (Dragon Goby) both frequent the 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.

Worth noting: Violet Goby (Dragon Goby) is nocturnal and will be most active after lights-out, naturally reducing daytime encounters. Also, Rachov's Killifish (Annual) is a known jumper, so a tight-fitting lid is essential.

The safe temperature window for both species falls between 23°C and 26°C. Aim for the midpoint of this range (around 24.5°C) for optimal comfort.

Both fish can tolerate a pH between 7.5 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 12–12 dGH. Regular testing will ensure conditions stay within this range.

Crucially, these species require different water types — one needs freshwater while the other requires brackish conditions. This is a hard barrier to keeping them together. An aquarium test kit is recommended for monitoring.

To house Rachov's Killifish (Annual) and Violet Goby (Dragon Goby) together, plan for an aquarium of at least 240 litres with a minimum length of 120 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: Soil / Nutrient Rich, Leaf Litter/Blackwater, Plants - Densely covered, Sand (Sifters), Shells (Breeding/Hiding), Driftwood (Digestion/Hiding). Meeting these requirements will help both species thrive.

Note a potential conflict in setup requirements: Rachov's Killifish (Annual) requires Soil / Nutrient Rich, while Violet Goby (Dragon Goby) requires Sand (Sifters). 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.