Compatibility Overview
Harlequin Rasbora 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 | Harlequin Rasbora | Silver Dollar | Verdict |
|---|---|---|---|
| Temperature | 72–81°F | 72–79°F | ✅ 72–79°F |
| pH Range | 5.5–7.5 | 6.0–7.0 | ✅ 6.0–7.0 |
| Temperament | peaceful | semi | ⚠️ Monitor |
| Adult Size | 1.75 in | 7.9 in | ❌ 5× difference |
| Min. Group | 8+ | 1+ | See below |
| Min. Tank Size | 100 gallons (for both species) | — | |
✅ Compatibility Positives
❌ Incompatibility Reasons
Species Profiles
Harlequin Rasbora — Trigonostigma heteromorpha
Active mid-level schooling fish with a distinctive black triangular patch. One of the best all-around community tank fish.
→ Full Harlequin Rasbora 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 Harlequin Rasbora live with Silver Dollar?
Generally not recommended. Harlequin Rasbora 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 Harlequin Rasbora and Silver Dollar together?
A minimum of 100 gallons is recommended for keeping Harlequin Rasbora and Silver Dollar together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Harlequin Rasbora and Silver Dollar?
72–79°F
Is a Harlequin Rasbora aggressive toward a Silver Dollar?
Harlequin Rasbora 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 | 100/100 |
| Ph | 100/100 |
| Temperament | 75/100 |
| Adult Size | 38/100 |
| 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. |