Can Rachov's Killifish (Annual) and Red Tail Barracuda Live Together?

Rachov's Killifish (Annual) is a generally mild-mannered species (3/10), while Red Tail Barracuda is semi-aggressive (7/10). This notable difference means Red Tail Barracuda may occasionally assert dominance over Rachov's Killifish (Annual).

Rachov's Killifish (Annual) and Red Tail Barracuda both frequent the 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.

There is a critical concern: the Nano / Bite-sized (Predation Risk) behaviour of one fish directly conflicts with the Piscivore (Eats small/nano fish) trait of the other — piscivorous fish will prey on nano-sized tank mates..

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.

Worth noting: Rachov's Killifish (Annual) is a known jumper, so a tight-fitting lid is essential.

The safe temperature window for both species falls between 24°C and 26°C. Aim for the midpoint of this range (around 25.0°C) for optimal comfort.

Both fish can tolerate a pH between 6 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.

To house Rachov's Killifish (Annual) and Red Tail Barracuda together, plan for an aquarium of at least 450 litres with a minimum length of 150 cm. This recommendation combines the stricter species minimums with a community-load allowance so the pairing has realistic long-term space and filtration headroom.

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, Smooth Gravel (Sensitive Barbels), Driftwood (Digestion/Hiding), Plants - Floating. Meeting these requirements will help both species thrive.

Note a potential conflict in setup requirements: Rachov's Killifish (Annual) requires Soil / Nutrient Rich, while Red Tail Barracuda requires Smooth Gravel (Sensitive Barbels). These substrate types may be difficult to provide simultaneously. Compromise where possible or prioritise the more critical need.

Rachov's Killifish (Annual) prefers Low (Still Water) flow while Red Tail Barracuda needs High (River/Stream) flow. Consider positioning filter outlets and using baffles to create zones of different current intensity within the same tank.

Rachov's Killifish (Annual) and Red Tail Barracuda are the kind of pair that can look acceptable in a shop but become a maintenance problem at home. The main risk is not a single number in the chart; it is the way incompatible behavior, water needs, or pressure on space compounds over time once both fish are established in the same tank.

Feeding time deserves special attention with this pairing. Red Tail Barracuda is a known shrimp eater and may prey on small invertebrates or nano fish like Rachov's Killifish (Annual).