Compatibility Overview
Bristlenose Pleco and Molly can generally share an aquarium with appropriate planning. Both species prefer overlapping temperature and pH ranges, and neither poses a major aggression risk to the other. A minimum 55-gallon tank is recommended to provide adequate territory and water volume for both species.
| Factor | Bristlenose Pleco | Molly | Verdict |
|---|---|---|---|
| Temperature | 60–80°F | 72–82°F | ✅ 72–80°F |
| pH Range | 6.5–7.5 | 7.5–8.5 | ⚠️ 7.5–7.5 (narrow) |
| Temperament | peaceful | peaceful | ✅ Compatible |
| Adult Size | 5 in | 4 in | ✅ Similar |
| Min. Group | 1+ | 3+ | See below |
| Min. Tank Size | 55 gallons (for both species) | — | |
✅ Compatibility Positives
⚠️ Caution Points
Species Profiles
Bristlenose Pleco — Ancistrus sp.
Hardy armoured catfish that grazes on algae. Peaceful with virtually all species; tolerates a wide temperature range.
→ Full Bristlenose Pleco care guide
Molly — Poecilia sphenops
Hardy livebearers that prefer alkaline, hard water — sometimes slightly brackish. Prolific breeders; peaceful community fish.
Frequently Asked Questions
Can Bristlenose Pleco live with Molly?
Yes, in a well-planned setup. Bristlenose Pleco and Molly can generally share an aquarium with appropriate planning. Both species prefer overlapping temperature and pH ranges, and neither poses a major aggression risk to the other. A minimum 55-gallon tank is recommended to provide adequate territory and water volume for both species.
What tank size do I need for Bristlenose Pleco and Molly together?
A minimum of 55 gallons is recommended for keeping Bristlenose Pleco and Molly together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Bristlenose Pleco and Molly?
72–80°F
Is a Bristlenose Pleco aggressive toward a Molly?
Bristlenose Pleco is peaceful and Molly is peaceful. pH ranges barely or do not overlap: Bristlenose Pleco prefers 6.5–7.5; Molly prefers 7.5–8.5.