Quick Stats
| Adult Size | 5 cm |
| Minimum Tank | 20 gal |
| Temperature | 24–28°C |
| pH Range | 4.5–6.5 |
| Hardness (GH) | 1–8 dGH |
| Difficulty | Medium |
| Temperament | Peaceful |
| Diet | Omnivore — micro pellets, frozen daphnia, baby brine shrimp |
| Schooling | 6–10+ rec. |
Tank Setup
The Cardinal Tetra (Paracheirodon axelrodi) requires a minimum tank size of 20 gal. For a species this size, a larger tank is always better — more water volume means more stable parameters and a healthier environment.
Water parameters should be maintained within the following ranges: temperature 24–28°C, pH 4.5–6.5, and hardness 1–8 dGH. These fish are sensitive to water quality — test regularly and maintain pristine conditions.
Provide appropriate hiding places, a suitable substrate, and planted areas to match the natural behaviour of this species.
Tank Mates
Cardinal Tetra are peaceful fish. They work well in community tanks with similarly-sized peaceful species.
Compatible tank mates include: Rummy Nose Tetra, Corydoras, Otocinclus, Apistogramma, Harlequin Rasbora. Avoid housing with aggressive or much larger fish.
Schooling requirements: 6–10+ rec.. Keeping them in adequate numbers is essential for their wellbeing.
Diet & Feeding
Cardinal Tetra are Omnivore. Feed a varied diet to ensure optimal health and colouration.
Omnivore — micro pellets, frozen daphnia, baby brine shrimp
Feed small amounts 1–2 times daily. Only provide what the fish can consume within 2–3 minutes to prevent overfeeding and water quality issues. Supplement with live or frozen foods for optimal health and colour.
Common Health Issues
Like all aquarium fish, Cardinal Tetra can be susceptible to common diseases including ich (white spot disease), fin rot, and bacterial infections. This species can be sensitive — maintain excellent water quality to prevent health issues.
Prevention is always better than treatment. Maintain stable water parameters, avoid overfeeding, quarantine new fish before adding them to the main tank, and perform regular water changes. Test your water weekly and address any parameter spikes immediately.
If disease does occur, isolate affected fish in a quarantine tank and treat appropriately. Always research medication compatibility before use — some treatments are toxic to invertebrates and scaleless fish.
Breeding
Breeding Cardinal Tetra requires specific conditions and may be challenging for beginners.
Provide appropriate breeding conditions — caves or hiding places for egg-laying species. Condition breeding pairs with high-quality foods before attempting to spawn them.
Research specific breeding requirements for this species before attempting it.
Frequently Asked Questions
What size tank does a Cardinal Tetra need?
A Cardinal Tetra needs a minimum tank size of 20 gal. However, larger is always better — more water volume means more stable water parameters and healthier fish.
Are Cardinal Tetra easy to keep?
Cardinal Tetra are rated as Medium difficulty. Some experience with aquarium water parameters is recommended before keeping this species.
What do Cardinal Tetra eat?
Cardinal Tetra are Omnivore. Feed a varied diet including micro pellets, frozen daphnia, baby brine shrimp.
Can Cardinal Tetra live with other fish?
Cardinal Tetra are peaceful. Compatible tankmates include: Rummy Nose Tetra, Corydoras, Otocinclus, Apistogramma, Harlequin Rasbora. They work well in community tanks with similarly-sized peaceful fish.