Can Apistogramma atahualpa and Red Swamp Crayfish Live Together?

Apistogramma atahualpa is a generally mild-mannered species (4/10), while Red Swamp Crayfish is highly aggressive (9/10). This notable difference means Red Swamp Crayfish may occasionally assert dominance over Apistogramma atahualpa.

Apistogramma atahualpa and Red Swamp Crayfish 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: Aggressive fish may bully and stress shy, slow-moving species. Hyperactive swimmers can stress shy, slow-moving species through constant motion. Two territorial species may clash over territory, especially in smaller tanks.

Worth noting: Red Swamp Crayfish is a known jumper, so a tight-fitting lid is essential.

The safe temperature window for both species falls between 24°C and 28°C. Aim for the midpoint of this range (around 26.0°C) for optimal comfort.

Both fish can tolerate a pH between 6.5 and 6.5. Maintaining a stable value within this band is more important than hitting an exact number.

Hardness requirements are incompatible: Apistogramma atahualpa needs 0–5 dGH while Red Swamp Crayfish requires 8–20 dGH.

To house Apistogramma atahualpa and Red Swamp Crayfish together, plan for an aquarium of at least 75 litres with a minimum length of 60 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: Sand (Sifters), Leaf Litter/Blackwater, Driftwood (Digestion/Hiding), Plants - Densely covered, Shells (Breeding/Hiding). Meeting these requirements will help both species thrive.

Note a potential conflict in setup requirements: Red Swamp Crayfish is a plant destroyer, which conflicts with Apistogramma atahualpa's requirement for live plants. 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.

Apistogramma atahualpa and Red Swamp Crayfish 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.