Can Cardinal Tetra and Florida Gar Live Together?

Cardinal Tetra is a peaceful species (1/10), while Florida Gar is semi-aggressive (7/10). This notable difference means Florida Gar may occasionally assert dominance over Cardinal Tetra.

Large aggression gap (6 points) between Cardinal Tetra and Florida Gar increases stress risk for the more peaceful fish.

Cardinal Tetra and Florida Gar 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.

Worth noting: Florida Gar is a known jumper, so a tight-fitting lid is essential.

The safe temperature window for both species falls between 24°C and 29°C. Aim for the midpoint of this range (around 26.5°C) for optimal comfort.

Both fish can tolerate a pH between 6 and 7. Maintaining a stable value within this band is more important than hitting an exact number.

For general hardness, the shared comfort zone is 8–8 dGH. Regular testing will ensure conditions stay within this range.

To house Cardinal Tetra and Florida Gar together, plan for an aquarium of at least 1100 litres with a minimum length of 240 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: Leaf Litter/Blackwater, Driftwood (Digestion/Hiding), Plants - Densely covered, Plants - Floating. Meeting these requirements will help both species thrive.

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

Cardinal Tetra and Florida Gar 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.