Can Otocinclus Catfish live with Silver Dollar?
Case-by-case. Watch group sizes, tank size, and feeding zones.
Why Otocinclus Catfish and Silver Dollar Don't Make an Easy Pair
They can coexist, but you need to manage the setup carefully. The temperament combination (peaceful+peaceful) can work, but you will need to watch them at feeding time for the first week.
Otocinclus Catfish
Otocinclus vittatus
| Adult Size: | 2.0" |
| Temperament: | peaceful |
| Min Tank: | 20 gal |
| Temperature: | 72-79°F |
| pH Range: | 6.5-7.5 |
Silver Dollar
Metynnis argenteus
| Adult Size: | 6.0" |
| Temperament: | peaceful |
| Min Tank: | 55 gal |
| Temperature: | 75-82°F |
| pH Range: | 6.0-7.5 |
Water Parameter Overlap
| Parameter | Otocinclus Catfish | Silver Dollar | Overlap |
|---|---|---|---|
| Temperature | 72-79°F | 75-82°F | 4°F ✓ |
| pH | 6.5-7.5 | 6.0-7.5 | 1.0 ✓ |
Compatibility Breakdown
Temperament Match: peaceful + peaceful. Both peaceful → minimal conflict.
⚠️ Size Predation Risk: Otocinclus Catfish (2.0") vs Silver Dollar (6.0"). A 4.0" gap — the larger fish will view the smaller fish as food.
Score: 60.0/100 (GOOD ≥80, CAUTION ≥50, RISKY <50).
🔧 Tank Setup Requirements (for Both)
- Minimum tank: 55 gallons — sized for the larger fish in the pair.
- Temperature: keep it between 75°F and 79°F.
- pH: maintain 6.5 – 7.5.
- Hiding spots: essential for Otocinclus Catfish — caves, plants, or driftwood to retreat when feeling stressed.
- Water changes: 25% weekly minimum. Two species mean double the bioload.
🔧 Tank Stocking Calculator
Enter tank size to calculate safe stocking levels:
Recommended Equipment
Based on tank size 55+ gallons:
Herbivore sinking rounds for plant-eating fish
Explore Related Checks
See what else works with these fish:
⚠️ Common Reasons This Pairing Fails in Practice
- Size-based predation: The 4.0" size gap means the larger fish may eat the smaller one once it grows to full size. This is not fixable with more hiding spots.
- Overcrowding: Even compatible species fail in tanks that are too small. Double the species means double the bioload — 25% weekly water changes are the minimum.
- Inadequate acclimation: Adding both species on the same day without quarantine is a common mistake. Always drip-acclimate new arrivals and quarantine for 2–4 weeks.
Tools & Resources
Accuracy note: This tool uses expert rules + FishBase.org data. Individual fish behavior varies — a peaceful individual Otocinclus Catfish may act differently from its species average. Always observe, quarantine new arrivals for 2-4 weeks, and avoid overcrowding. If a pairing says CAUTION, start with a smaller group and a lid.