Compatibility Overview
Otocinclus 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 | Otocinclus | Silver Dollar | Verdict |
|---|---|---|---|
| Temperature | 72–82°F | 72–79°F | ✅ 72–79°F |
| pH Range | 6.0–7.5 | 6.0–7.0 | ✅ 6.0–7.0 |
| Temperament | peaceful | semi | ⚠️ Monitor |
| Adult Size | 1.5 in | 7.9 in | ❌ 5× difference |
| Min. Group | 4+ | 1+ | See below |
| Min. Tank Size | 100 gallons (for both species) | — | |
✅ Compatibility Positives
❌ Incompatibility Reasons
Species Profiles
Otocinclus — Otocinclus spp.
Tiny algae-eating catfish that are peaceful with all species. Need established algae growth and biofilm; sensitive to ammonia.
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 Otocinclus live with Silver Dollar?
Generally not recommended. Otocinclus 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 Otocinclus and Silver Dollar together?
A minimum of 100 gallons is recommended for keeping Otocinclus and Silver Dollar together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Otocinclus and Silver Dollar?
72–79°F
Is a Otocinclus aggressive toward a Silver Dollar?
Otocinclus 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 | 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 | 180 gal | Best when keeping larger schools or reducing territorial pressure. |