Compatibility Overview
Cardinal Tetra and Otocinclus can generally share an aquarium with appropriate planning. Both species prefer overlapping temperature and pH ranges, and neither poses a major aggression risk to the other. A minimum 30-gallon tank is recommended to provide adequate territory and water volume for both species.
| Factor | Cardinal Tetra | Otocinclus | Verdict |
|---|---|---|---|
| Temperature | 73–82°F | 72–82°F | ✅ 73–82°F |
| pH Range | 4.5–7.0 | 6.0–7.5 | ✅ 6.0–7.0 |
| Temperament | peaceful | peaceful | ✅ Compatible |
| Adult Size | 1.5 in | 1.5 in | ✅ Similar |
| Min. Group | 6+ | 4+ | See below |
| Min. Tank Size | 30 gallons (for both species) | — | |
✅ Compatibility Positives
⚠️ Caution Points
Species Profiles
Cardinal Tetra — Paracheirodon axelrodi
Brilliant red-and-blue schooling fish from the Rio Negro. Prefers soft, acidic, warm water — a natural companion for discus.
→ Full Cardinal Tetra care guide
Otocinclus — Otocinclus spp.
Tiny algae-eating catfish that are peaceful with all species. Need established algae growth and biofilm; sensitive to ammonia.
Frequently Asked Questions
Can Cardinal Tetra live with Otocinclus?
Yes, in a well-planned setup. Cardinal Tetra and Otocinclus can generally share an aquarium with appropriate planning. Both species prefer overlapping temperature and pH ranges, and neither poses a major aggression risk to the other. A minimum 30-gallon tank is recommended to provide adequate territory and water volume for both species.
What tank size do I need for Cardinal Tetra and Otocinclus together?
A minimum of 30 gallons is recommended for keeping Cardinal Tetra and Otocinclus together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Cardinal Tetra and Otocinclus?
73–82°F
Is a Cardinal Tetra aggressive toward a Otocinclus?
Cardinal Tetra is peaceful and Otocinclus is peaceful. No major aggression issues are expected between these species.