Compatibility Overview
Cardinal Tetra and Silver Dollar are generally not recommended to be housed together. The issues listed above — whether water parameter incompatibility, predation risk, or aggression — create conditions where one or both fish are likely to suffer harm or chronic stress.
| Factor | Cardinal Tetra | Silver Dollar | Verdict |
|---|---|---|---|
| Temperature | 73–82°F | 72–79°F | ✅ 73–79°F |
| pH Range | 4.5–7.0 | 6.0–7.0 | ✅ 6.0–7.0 |
| Temperament | peaceful | semi | ⚠️ Monitor |
| Adult Size | 1.5 in | 7.9 in | ❌ 5× difference |
| Min. Group | 6+ | 1+ | See below |
| Min. Tank Size | 100 gallons (for both species) | — | |
✅ Compatibility Positives
❌ Incompatibility Reasons
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
Silver Dollar — Aquarium species
The Metynnis argenteus, known as the Silver Dollar fish, is a popular freshwater species with a distinctive silver color and disc-shaped body. They require a spacious tank and are best kept in groups to prevent bullying. Their peaceful nature makes them suitable for community tanks, but they are not known to school. They thrive in a well-maintained environme
Frequently Asked Questions
Can Cardinal Tetra live with Silver Dollar?
Generally not recommended. Cardinal Tetra and Silver Dollar are generally not recommended to be housed together. The issues listed above — whether water parameter incompatibility, predation risk, or aggression — create conditions where one or both fish are likely to suffer harm or chronic stress.
What tank size do I need for Cardinal Tetra and Silver Dollar together?
A minimum of 100 gallons is recommended for keeping Cardinal Tetra and Silver Dollar together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Cardinal Tetra and Silver Dollar?
73–79°F
Is a Cardinal Tetra aggressive toward a Silver Dollar?
Cardinal Tetra is peaceful and Silver Dollar is semi. The adult size gap creates a meaningful predation risk.
Related Compatibility Guides
Compatibility score breakdown
The overall score is weighted across water chemistry, behavior, adult size, swimming zone, and social needs. A score is a planning aid—not a guarantee for individual fish.
| Factor | Score |
|---|---|
| Temperature | 86/100 |
| Ph | 100/100 |
| Temperament | 75/100 |
| Adult Size | 8/100 |
| Swim Zone | 68/100 |
| Social Needs | 92/100 |
Tank size scenarios
Use the scenario that matches the actual group sizes and temperament you plan to keep.
| Scenario | Tank | When it applies |
|---|---|---|
| Minimum viable | 100 gal | Only for the recommended minimum groups, mature filtration, and close monitoring. |
| Recommended community | 150 gal | Adds territory, swimming room, and a safer buffer for behavior. |
| Low-conflict setup | 220 gal | Best when keeping larger schools or reducing territorial pressure. |