|Synonyms||Cheirodon axelrodi, Hyphessobrycon cardinalis|
|Distribution||South America: Upper Orinoco and Negro River Basins.|
|Sexual Dimorphism||Males are usually slightly smaller and slimmer than females of the same age.|
|Maximum Size||2.5cm (1”)|
|Water Parameters||Soft and acidic. pH: 4.0-6.0, dH: 5-12 degrees.|
|Temperature||23-27 deg C (73-81 deg F)|
|Lighting||No special requirements|
A very beautiful and peaceful species which should be maintained in groups of 6 or more. Only suitable for mature softwater aquariums and careful acclimatisation is essential. Exposure to hard water will cause kidney damage to the fish and result in premature death. The aquarium should be well-planted, and contain other small peaceful fish species. Their native waters are coloured with tannins and are very slow moving.
Offer a varied diet including a good quality flake, micropellets, and small frozen foods such as mosquito larvae and daphnia. Challenging to breed in the home aquarium.
The water must be extremely soft and acidic, and because Cardinal Tetras are thought to lay their eggs in darkness, the spawning aquarium must be darkened. It is a good idea to place a grid or a layer of sterilised marbles on the bottom of the spawning tank in order to protect the eggs from the parents. The temperature should be set at the higher end of their range. Female Cardinal Tetras can lay upwards of 150 eggs, some report over 300. Once the eggs have been laid/fertilised, the pair should be acclimatised back to the main aquarium. As the eggs are photo-sensitive, they should remain in darkness, and should hatch within 36 hours. Once the fry have absorbed their yolk sacs and become free-swimming, much difficulty in feeding them ensues, this being due to their diminutive size. Infusoria and liquid fry foods should be offered, moving on to newly hatched brineshrimp after a week or so. Remember that the fry are also light-sensitive and should remain under very subdued lighting (and stable water conditions) for some time.