Can Butterfly Goodeid and Cardinal Tetra Live Together?

Butterfly Goodeid is a moderately assertive species (6/10), while Cardinal Tetra is peaceful (1/10). This notable difference means Butterfly Goodeid may occasionally assert dominance over Cardinal Tetra.

Butterfly Goodeid and Cardinal Tetra 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.

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 26°C. Aim for the midpoint of this range (around 25.0°C) for optimal comfort.

Both fish can tolerate a pH between 7 and 7. Maintaining a stable value within this band is more important than hitting an exact number.

Hardness requirements are incompatible: Butterfly Goodeid needs 10–25 dGH while Cardinal Tetra requires 1–8 dGH.

To house Butterfly Goodeid and Cardinal Tetra together, plan for an aquarium of at least 110 litres with a minimum length of 80 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: Established Algae (Otocinclus), Plants - lighly covered, Leaf Litter/Blackwater, Driftwood (Digestion/Hiding), Plants - Densely covered. Meeting these requirements will help both species thrive.

Note a potential conflict in setup requirements: Butterfly Goodeid is a plant destroyer, which conflicts with Cardinal Tetra's requirement for live plants. Compromise where possible or prioritise the more critical need.

Both species do well with moderate (standard) water movement, so a standard filtration setup rated for the tank volume should suffice.

Butterfly Goodeid and Cardinal Tetra 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.