Can German Blue Ram live with Oscar?
High risk due to water mismatch, aggression, or predation.
Why German Blue Ram and Oscar Don't Make an Easy Pair
The size gap is 9.5" — German Blue Ram (2.5") and Oscar (12.0"). A fish that fits in another fish's mouth will eventually end up there.
German Blue Ram
Mikrogeophagus ramirezi
| Adult Size: | 2.5" |
| Temperament: | peaceful |
| Min Tank: | 20 gal |
| Temperature: | 78-86°F |
| pH Range: | 5.0-7.0 |
Oscar
Astronotus ocellatus
| Adult Size: | 12.0" |
| Temperament: | aggressive |
| Min Tank: | 75 gal |
| Temperature: | 74-81°F |
| pH Range: | 6.0-7.5 |
Water Parameter Overlap
| Parameter | German Blue Ram | Oscar | Overlap |
|---|---|---|---|
| Temperature | 78-86°F | 74-81°F | 3°F ✓ |
| pH | 5.0-7.0 | 6.0-7.5 | 1.0 ✓ |
Compatibility Breakdown
Temperament Match: peaceful + aggressive. One aggressive → predation/nipping risk.
⚠️ Size Predation Risk: German Blue Ram (2.5") vs Oscar (12.0"). A 9.5" gap — the larger fish will view the smaller fish as food.
⚠️ Diet Conflict: A carnivore sharing water with a fish small enough to fit in its mouth is a waiting game. Feed generously, but the risk is structural — not something you can manage meal by meal.
Score: 35.0/100 (GOOD ≥80, CAUTION ≥50, RISKY <50).
🔧 Tank Setup Requirements (for Both)
- Minimum tank: 75 gallons — sized for the larger fish in the pair.
- Temperature: keep it between 78°F and 81°F.
- pH: maintain 6.0 – 7.0.
- Hiding spots: essential for German Blue Ram — 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 75+ gallons:
High-capacity canister filter for oscar tanks
Explore Related Checks
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Accuracy note: This tool uses expert rules + FishBase.org data. Individual fish behavior varies — a peaceful individual German Blue Ram 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.