Can Apistogramma elizabethae and Dusky Millions Fish Live Together?

Apistogramma elizabethae is a moderately assertive species (5/10), while Dusky Millions Fish is peaceful (2/10). This modest difference means Apistogramma elizabethae may occasionally assert dominance over Dusky Millions Fish.

In terms of spatial distribution, Apistogramma elizabethae prefers the Bottom (Substrate) zone, whereas Dusky Millions Fish occupies the Top (Surface) and Middle (Open Water) zones. Because they use different levels of the water column, territorial disputes are less likely and the tank will appear more balanced.

Additional behavioural considerations to keep in mind: Hyperactive swimmers can stress shy, slow-moving species through constant motion.

The safe temperature window for both species falls between 24°C and 24°C. Aim for the midpoint of this range (around 24.0°C) for optimal comfort.

The pH requirements of Apistogramma elizabethae (4–6.5) and Dusky Millions Fish (7–8) do not overlap, making it impossible to satisfy both species simultaneously.

Hardness requirements are incompatible: Apistogramma elizabethae needs 0–5 dGH while Dusky Millions Fish requires 8–20 dGH.

To house Apistogramma elizabethae and Dusky Millions Fish together, plan for an aquarium of at least 55 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, Plants - Floating, Established Algae (Otocinclus). Meeting these requirements will help both species thrive.

Note a potential conflict in setup requirements: Dusky Millions Fish is a plant destroyer, which conflicts with Apistogramma elizabethae'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 elizabethae and Dusky Millions Fish 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.