Compatibility Overview
Cardinal Tetra and Guppy 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 40-gallon tank is recommended to provide adequate territory and water volume for both species.
| Factor | Cardinal Tetra | Guppy | Verdict |
|---|---|---|---|
| Temperature | 73–82°F | 72–82°F | ✅ 73–82°F |
| pH Range | 4.5–7.0 | 6.8–8.5 | ⚠️ 6.8–7.0 (narrow) |
| Temperament | peaceful | peaceful | ✅ Compatible |
| Adult Size | 1.5 in | 2.5 in | ✅ Similar |
| Min. Group | 6+ | 3+ | See below |
| Min. Tank Size | 40 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
Guppy — Poecilia reticulata
Hardy and colourful livebearers. Males' long flowing tails make them targets for fin-nipping species. Very prolific breeders.
Frequently Asked Questions
Can Cardinal Tetra live with Guppy?
Yes, in a well-planned setup. Cardinal Tetra and Guppy 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 40-gallon tank is recommended to provide adequate territory and water volume for both species.
What tank size do I need for Cardinal Tetra and Guppy together?
A minimum of 40 gallons is recommended for keeping Cardinal Tetra and Guppy together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Cardinal Tetra and Guppy?
73–82°F
Is a Cardinal Tetra aggressive toward a Guppy?
Cardinal Tetra is peaceful and Guppy is peaceful. pH ranges barely or do not overlap: Cardinal Tetra prefers 4.5–7.0; Guppy prefers 6.8–8.5.