Cardinal tetra
Paracheirodon axelrodi
The neon's close cousin, with red running the full length of the belly; a soft, acidic-water schooling fish that likes it warmer than neons.
Key facts
- Body length
- 1.4 in without fins
- Minimum tank
- 17 gallons
- Group
- 8+
- Temperament
- Peaceful
- Care level
- 3 / 5
- Lifespan
- 1–5 years
- Diet
- Micro pellets, flakes, frozen daphnia and brine shrimp
- Origin
- Rio Negro and Orinoco basins, South America
- Hardier than77%
- Bigger than12%
- Calmer than68%
Water: their range vs yours
Cardinal tetra tank mates
- Neon tetraGets along in shared water.Good mates
- Harlequin rasboraGets along in shared water.Good mates
- Fancy guppyGets along in shared water.Good mates
- Panda corydorasGets along in shared water.Good mates
- OtocinclusGets along in shared water.Good mates
- Cherry shrimpGets along in shared water.Good mates
- BettaGets along in shared water.Good mates
- Tiger barbGets along in shared water.Good mates
- Amano shrimpGets along in shared water.Good mates
- Black neon tetraGets along in shared water.Good mates
- Black widow tetraGets along in shared water.Good mates
- Blood parrot cichlidGets along in shared water.Good mates
- Chinese algae eaterChinese algae eater attacks fish with a similar shape or colour: Cardinal tetra.Risky
- Clown loachClown loach attacks fish with a similar shape or colour: Cardinal tetra.Risky
- DemasoniDemasoni attacks fish with a similar shape or colour: Cardinal tetra.Risky
- Golden mbunaGolden mbuna attacks fish with a similar shape or colour: Cardinal tetra.Risky
- Peacock cichlidMalawi butterfly peacock attacks fish with a similar shape or colour: Cardinal tetra.Risky
- Rainbow sharkRainbow shark attacks fish with a similar shape or colour: Cardinal tetra.Risky
- AngelfishAngelfish can eat Cardinal tetra: prey body depth 0.8 cm ≤ mouth 2.3 cm.Avoid
- Blue dolphin cichlidBlue dolphin cichlid can eat Cardinal tetra: prey body depth 0.8 cm ≤ mouth 6.3 cm.Avoid
- Convict cichlidConvict cichlid can eat Cardinal tetra: prey body depth 0.8 cm ≤ mouth 3.8 cm.Avoid
- Firemouth cichlidFiremouth cichlid can eat Cardinal tetra: prey body depth 0.8 cm ≤ mouth 3.0 cm.Avoid
- GoldfishGoldfish can eat Cardinal tetra: prey body depth 0.8 cm ≤ mouth 3.0 cm.Avoid
- Iridescent sharkIridescent shark can eat Cardinal tetra: prey body depth 0.8 cm ≤ mouth 32.5 cm.Avoid
How we check
The numbers the tank model uses for cardinal tetras: water as ideal and tolerated ranges, bioload from adult mass, space, flow and how they act on other species.
- Standard length
- 3.5 cm (SL)
- Adult mass
- 1.06 g
- Bioload at 25 °C
- 1.01 BU
- Min. water
- 54 L net
- Min. footprint
- 60 × 30 cm per group
- Group
- 8+ (best 10)
- Swims in
- middle
- Flow
- low
- Body / fins
- fusiform, normal fins
- Diet type
- micropredator
- Fin nipper
- none
- Sensitive to
- —
Sources: Seriously Fish: Paracheirodon axelrodi · FishBase: Paracheirodon axelrodi
Care notes
Cardinal tetras come from the blackwaters of the Rio Negro and clearwater streams of the Orinoco. Almost all fish on sale are wild-caught, which makes them more sensitive to water quality than neon tetras.
Keep eight to ten or more in a 15 gallon tank or larger at 73–84°F, ideally in soft water below pH 7. They suit warm planted tanks, but large angelfish may treat them as food.
Questions
What size tank does a cardinal tetra need?
At least 17 gallons (54 litres of water after decor). Adults reach about 1.4 inches without fins.
How many cardinal tetras should be kept together?
Keep at least 8, ideally 10 or more: fewer feel exposed and hide or turn nippy.
What water do cardinal tetras need?
73–81 °F, pH 4–6 and 1–12 dGH. Cardinal tetras come from Rio Negro and Orinoco basins, South America.
How long do cardinal tetras live?
1–5 years with good care.
What fish can live with cardinal tetras?
Good tank mates include Neon tetra, Harlequin rasbora, Fancy guppy, Panda corydoras and Otocinclus. Each is checked both ways for size, fin nipping, temperament, territory and shared water.