Can Least Killifish Live With Oscar?
Least Killifish and Oscar are NOT compatible tank mates.
Detailed Analysis
Temperature
✓ Compatible
Good temperature overlap at 74–80°F.
pH
✓ Compatible
Good pH overlap at 6.5–7.5.
Size
✗ Not Compatible
Extreme size difference. Oscar (14") may eat or bully Least Killifish (1").
Temperament
✗ Not Compatible
Least Killifish (peaceful) is not compatible with Oscar (aggressive). Aggression or stress is very likely.
Swim Level
✓ Compatible
Fish occupy different water levels (Least Killifish: top, Oscar: middle), reducing conflict.
Trait Conflict
✗ Not Compatible
Oscar is a predator and may eat Least Killifish.
Important Notes
- Least Killifish is a schooling fish and needs at least 4 of its kind.
Tank Requirements
Minimum tank size for this combination: 75 gallons
| Parameter | Least Killifish | Oscar |
|---|---|---|
| Temperature | 66–80°F | 74–81°F |
| pH | 6.5–8 | 6–7.5 |
| Max Size | 1" | 14" |
| Temperament | Peaceful | Aggressive |
| Swim Level | Top | Middle |
| Min Tank | 5 gal | 75 gal |
Check More Combinations
Use our compatibility checker to add more fish and plan your complete tank.