Cardinal Terta

The Cardinal Tetra (Paracheirodon axelrodi) is a hugely popular freshwater fish known for its stunning, iridescent coloration, which features a neon-blue stripe sitting directly above a vibrant, blood-red stripe that runs the entire length of its body. They are a classic choice for planted, community aquariums.

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Cardinal Tetra Care and Profile

 

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Tank Requirements and Water Parameters

 

Cardinal Tetras are native to slow-moving, heavily shaded “blackwater” or “clearwater” streams and are more sensitive to water quality fluctuations than their close relative, the Neon Tetra.

• Minimum Tank Size: 20 gallons is recommended for a school of six or more. They need a long tank with plenty of swimming space.
• Schooling: They must be kept in schools of at least 6-10 individuals. Keeping them in large groups reduces stress, enhances their coloring, and prevents shy or skittish behavior.
• Temperature: A stable tropical temperature is crucial: 73°–81° F (23°–27° C).
• pH Level: They thrive in soft, acidic water, ideally below 6.5. While tank-raised fish can tolerate up to 7.5, a pH range of 5.0–6.2 is preferred for optimal health and breeding.
• Water Hardness: Very soft water is essential, preferably below 4 dGH. High mineral content is a common cause of poor health in Cardinals.

 

Habitat Setup

 

To best replicate their natural, shaded environment:

1. Lighting: Use subdued or dim lighting. Floating plants (like frogbit or water lettuce) or tall, dense background plants (like Amazon Swords or Water Sprite) are excellent for diffusing the light.
2. Substrate & Decor: Use a dark substrate (sand or fine gravel) to make their colors truly pop. Add driftwood and leaf litter (such as Indian Almond Leaves) to release beneficial tannins, which help lower the pH and mimic the blackwater look.
3. Filtration: A reliable filter (like a canister or HOB) is needed, but the water flow should be gentle. They do not like strong currents.

 

Diet and Feeding

 

The Cardinal Tetra is an omnivore and a micropredator.

• Staple Diet: Feed a high-quality, small flake food or micro-pellet, as they have tiny mouths.
• Supplementation: Their colors and health benefit greatly from regular feeding of live or frozen meaty foods like daphnia, brine shrimp, and bloodworms.
• Feeding Schedule: Feed small amounts 2-3 times per day, only what they can consume in 2-3 minutes, to prevent water fouling.

 

Compatibility

 

Cardinal Tetras are peaceful and do well with other calm, similarly sized fish. Good tank mates include:

• Other small, peaceful Tetras (Neon, Black Skirt, Ember)
• Peaceful bottom-dwellers (Corydoras Catfish)
• Small, gentle cichlids (German Blue Rams)
• Rasboras and Dwarf Gourami

Avoid any large or aggressive fish, as Cardinals are small and can easily become stressed or seen as prey.