Can Lawnmower Blenny live with Silver Arowana?
Case-by-case. Watch group sizes, tank size, and feeding zones.
Why Lawnmower Blenny and Silver Arowana Don't Make an Easy Pair
They can coexist, but you need to manage the setup carefully. The temperament combination (peaceful+semi-aggressive) can work, but you will need to watch them at feeding time for the first week.
Lawnmower Blenny
Salarias fasciatus
| Adult Size: | 5.0" |
| Temperament: | peaceful |
| Min Tank: | 30 gal |
| Temperature: | 74-82°F |
| pH Range: | 8.1-8.4 |
Silver Arowana
Osteoglossum bicirrhosum
| Adult Size: | 36.0" |
| Temperament: | semi-aggressive |
| Min Tank: | 250 gal |
| Temperature: | 75-82°F |
| pH Range: | 6.0-7.5 |
Water Parameter Overlap
| Parameter | Lawnmower Blenny | Silver Arowana | Overlap |
|---|---|---|---|
| Temperature | 74-82°F | 75-82°F | 7°F ✓ |
| pH | 8.1-8.4 | 6.0-7.5 | No overlap ✗ |
Compatibility Breakdown
Temperament Match: peaceful + semi-aggressive. Semi-aggressive → watch territory and feeding.
⚠️ Size Predation Risk: Lawnmower Blenny (5.0") vs Silver Arowana (36.0"). A 31.0" 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: 60/100 (GOOD ≥80, CAUTION ≥50, RISKY <50).
🔧 Tank Setup Requirements (for Both)
- Minimum tank: 250 gallons — sized for the larger fish in the pair.
- Temperature: keep it between 75°F and 82°F.
- pH: no shared range. One species will be outside its tolerance regardless of what you set.
- Hiding spots: essential for Lawnmower Blenny — 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 250+ gallons:
Floating food sticks for large carnivorous surface feeders
Explore Related Checks
See what else works with these fish:
Accuracy note: This tool uses expert rules + FishBase.org data. Individual fish behavior varies — a peaceful individual Lawnmower Blenny 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.