Can Electric Blue Crayfish live with Molly?
These two species are usually compatible in community tanks.
Why Electric Blue Crayfish and Molly Work
These two species overlap in both temperature (72–80°F overlap) and pH (7.0-8.0 overlap range). Their temperature tolerances are close enough, and neither fish pushes the pH so far outside the other's comfort zone that it creates chronic stress. The temperament match (aggressive + peaceful) is low-conflict. In a 30+ gallon tank with adequate hiding spots, these two can coexist with minimal problems.
Electric Blue Crayfish
Procambarus alleni
| Adult Size: | 6.0" |
| Temperament: | aggressive |
| Min Tank: | 30 gal |
| Temperature: | 65-80°F |
| pH Range: | 6.5-8.0 |
Molly
Poecilia sphenops
| Adult Size: | 4.5" |
| Temperament: | peaceful |
| Min Tank: | 20 gal |
| Temperature: | 72-82°F |
| pH Range: | 7.0-8.0 |
Water Parameter Overlap
| Parameter | Electric Blue Crayfish | Molly | Overlap |
|---|---|---|---|
| Temperature | 65-80°F | 72-82°F | 8°F ✓ |
| pH | 6.5-8.0 | 7.0-8.0 | 1.0 ✓ |
Compatibility Breakdown
Temperament Match: aggressive + peaceful. One aggressive → predation/nipping risk.
Score: 115.0/100 (GOOD ≥80, CAUTION ≥50, RISKY <50).
🔧 Tank Setup Requirements (for Both)
- Minimum tank: 30 gallons — sized for the larger fish in the pair.
- Temperature: keep it between 72°F and 80°F.
- pH: maintain 7.0 – 8.0.
- Hiding spots: essential for Molly — 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 30+ gallons:
Sinking food for crayfish and crustaceans
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 aggressive individual Electric Blue Crayfish 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.