Compatibility Overview
Royal Gramma 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 | Royal Gramma | Silver Dollar | Verdict |
|---|---|---|---|
| Temperature | 73–81°F | 72–79°F | ✅ 73–79°F |
| pH Range | 8.0–8.5 | 6.0–7.0 | ❌ No overlap |
| Temperament | semi | semi | ⚠️ Monitor |
| Adult Size | 1.6 in | 7.9 in | ❌ 5× difference |
| Min. Group | 1+ | 1+ | See below |
| Min. Tank Size | 75 gallons (for both species) | — | |
✅ Compatibility Positives
❌ Incompatibility Reasons
Species Profiles
Royal Gramma — Aquarium species
The Royal Gramma, known for its vibrant blue coloration, is a popular saltwater fish among beginners and experienced aquarists alike. It requires a well-maintained tank with plenty of swimming space and a moderate current. With a peaceful temperament and a relatively easy care routine, the Royal Gramma can be a great addition to a community tank. Its delicat
→ Full Royal Gramma 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 Royal Gramma live with Silver Dollar?
Generally not recommended. Royal Gramma 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 Royal Gramma and Silver Dollar together?
A minimum of 75 gallons is recommended for keeping Royal Gramma and Silver Dollar together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Royal Gramma and Silver Dollar?
73–79°F
Is a Royal Gramma aggressive toward a Silver Dollar?
Royal Gramma is semi and Silver Dollar is semi. These animals require different water types and cannot share one aquarium.
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 | 0/100 |
| Temperament | 62/100 |
| 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 | 75 gal | Only for the recommended minimum groups, mature filtration, and close monitoring. |
| Recommended community | 125 gal | Adds territory, swimming room, and a safer buffer for behavior. |
| Low-conflict setup | 150 gal | Best when keeping larger schools or reducing territorial pressure. |