Cardinal Tetra care

Paracheirodon axelrodi · Freshwater · Intermediate level care

A bright red and blue schooling fish that likes warm, soft, slightly acidic water.

Smallest tank20 gallons

Adult size2 inches

Temperature76 to 82°F

pH5 to 7

GroupA group of 8 or more

TemperamentPeaceful

SwimsMiddle of the tank

Lives4 to 5 years

Watch for: Water that is too hard or too cool leads to stress and sickness.

Feeding

Twice a day. A small pinch they finish in about 2 minutes. Micro pellets, crushed flakes, frozen daphnia.

Fish that pass every check with Cardinal Tetra in a 40 gallon tank: same water, overlapping temperature, nobody gets eaten and no bullies.

Silver Dollar: Silver Dollar grows big enough to eat Cardinal Tetra.
Rosy Barb: Rosy Barb and Cardinal Tetra need different water temperatures.
Tinfoil Barb: Tinfoil Barb grows big enough to eat Cardinal Tetra.
Gold Barb: Gold Barb and Cardinal Tetra need different water temperatures.
White Cloud Mountain Minnow: White Cloud Mountain Minnow and Cardinal Tetra need different water temperatures.
Paradise Fish: Paradise Fish and Cardinal Tetra need different water temperatures.
Angelfish: Angelfish grows big enough to eat Cardinal Tetra.
Convict Cichlid: Convict Cichlid grows big enough to eat Cardinal Tetra.

What size tank does a Cardinal Tetra need?

At least 20 gallons for a group of 8. Adults grow to about 2 inches, so plan for the adult size, not the size at the store.

What temperature does a Cardinal Tetra like?

76 to 82 degrees Fahrenheit, with a pH of about 5 to 7. A steady temperature matters more than hitting one exact number.

How many Cardinal Tetra should I keep together?

Keep 8 or more. They feel safe in a group and show better color and behavior.

What do Cardinal Tetra eat?

Micro pellets, crushed flakes, frozen daphnia. Feed twice a day: a small pinch they finish in about 2 minutes.

Checked against these sources on 2026-11-10. When sources disagree we use the safer number.