Cardenal Tetra WC (0,75-1”)

Scientific Name:

Paracheirodon axelrodi

Maximum Size and Lifespan:

• Size: Up to 2 inches (5 cm)

• Lifespan: Typically 4–5 years in captivity with excellent care; occasionally longer

Recommended Aquarium Size, Water Changes & Care:

• Minimum Aquarium Size:

  • 10 gallons (75 liters) for a small school (minimum of 6–8 fish)

  • A larger tank (30+ gallons) is better for stability and bigger groups also if keeping with other fish.

• Water Parameters:

  • Temperature: 75–82°F (23–27°C)

  • pH: 5.5-7.5 (soft, acidic water preferred)

• Water Changes:

  • 20–40% Weekly Maintain stable water quality—Cardinals are sensitive to fluctuations

• Care Notes:

  • Peaceful and schooling; should always be kept in groups of at least 6, ideally 10+

  • Require a mature, well-cycled tank with stable parameters

  • Dim lighting and planted aquascapes mimic their natural habitat and reduce stress

  • Great for community tanks with other peaceful species that prefer soft water 

   

• Tankmates
• They do best with other small peaceful community fish. 
• Bushynose pleco, Rummynose Tetra, Kuhli Loaches, Rasboras, Dwarf Rainbowfish, Corydoras, etc.

Diet:

• Type: Omnivorous

• Captive Diet:

  • High-quality micro pellets, flakes, and frozen/Live baby brine shrimp

  • Xtreme Nano Pellets are the best pellet for them

• Feeding Frequency:

  • 1–2 small feedings per day

  • Only feed what they consume in 2–3 minutes

Overview (Before Natural Habitat):

Cardinal Tetras are among the most visually striking small tropical fish, known for their brilliant neon blue stripe and vivid red underside extending from nose to tail—unlike the similar Neon Tetra (Paracheirodon innesi), whose red coloring ends mid-body. Cardinals are peaceful, social fish ideal for naturalistic, planted aquariums. While hardy when acclimated, they need pristine, stable water and do best in soft, acidic conditions. Their behavior is calm, and they prefer slow-moving water and the cover of plants or driftwood. They thrive in biologically balanced aquaria with tannin-stained water and low light.

Natural Environment:

• Habitat: Blackwater rivers of South America, especially:

  • Rio Negro (Brazil)

  • Orinoco River Basin (Venezuela and Colombia)

• Conditions:

  • Warm, slow-moving water with high levels of humic acids (tannins)

  • Dense leaf litter, submerged branches, and shaded areas

  • Very low conductivity and pH

Breeding:

• Difficulty: Moderate to Difficult in home aquariums

• Breeding Conditions:

  • Separate breeding tank with very soft (0–2 dGH), acidic water (pH 4.0–5.5), and temperature of 80–84°F (27–29°C)

  • Low light or complete darkness triggers spawning

  • Pairs or small groups may spawn in dim light early in the day

• Spawning Behavior:

  • Eggs are scattered among plants or fine-leaved spawning mops

  • Remove adults post-spawning as they will eat the eggs

• Egg/Fry Care:

  • Eggs hatch in ~24–36 hours; fry are free-swimming in ~4–5 days

  • Feed fry Live baby brine shrimp

  • Extremely sensitive to water quality early in life