What size tank does a Cardinal Tetra need?

Cardinal Tetra needs a minimum of 10 gallons, with 20 gallons recommended. They are middle swimmers. Keep in groups of 6+.

Is Cardinal Tetra good for beginners?

Cardinal Tetra is rated "intermediate" difficulty (2/5). Great for beginners.

What fish are compatible with Cardinal Tetra?

Cardinal Tetra is peaceful. Compatible tank mates include other peaceful fish with similar water parameters (pH 4.5-6.5, temp 73-81°F).

Cardinal Tetra

Paracheirodon axelrodi

Family: Characidae • Origin: South America

The Cardinal Tetra has a red stripe extending the full length of its body. Prefers soft acidic water and shows richer coloration in blackwater setups.

Min Tank

10 gal

Max Size

Temperature

73-81°F

4.5-6.5

Lifespan

4 years

School Size

Swim Level

middle

Hardness

1-5 dGH

peacefulintermediateomnivoreschooling

Is Cardinal Tetra Right for Your Tank?

Cardinal Tetra is an excellent choice for beginners — rated "intermediate" difficulty (2/5). They're hardy, forgiving of minor water parameter fluctuations, and generally easy to feed. At just 10 gallons minimum, they work well in nano tanks and smaller setups.

With a peaceful temperament, Cardinal Tetra makes a great community fish. They coexist well with other non-aggressive species of similar size. This is a schooling species — keep at least 6 together, or they may become stressed and display abnormal behavior. Expected lifespan: 4 years with proper care.

Common Mistakes with Cardinal Tetra

✗

Keeping fewer than 6 together

Cardinal Tetra is a schooling species — they need a group of at least 6 to feel secure. Lone or paired individuals become stressed, hide constantly, and may develop health issues or aggression.

✗

Relying on a heater without a thermometer

Cardinal Tetra needs 73–81°F. Heaters malfunction or drift over time — always use a separate thermometer to verify. Temperature swings of even 3–4°F can trigger stress and disease, particularly ich.

✗

Putting them in a tank under 10 gallons

While 10 gallons is the minimum, nano tanks require more frequent water changes and leave less room for error. A slightly larger tank (20 gal) is much more forgiving.