Molly and Pajama Cardinalfish Compatibility Overview
Molly and Pajama Cardinalfish are generally not recommended to be housed together. One of these is a marine species and the other is not; they cannot share one aquarium. Their usable pH overlap is narrow and requires stable, tested water. Review the behavior and water details before deciding whether to attempt the pairing.
| Factor | Molly | Pajama Cardinalfish | Verdict |
|---|---|---|---|
| Temperature | 72โ82ยฐF | 72โ82ยฐF | โ 72โ82ยฐF |
| pH Range | 7.5โ8.5 | 8.1โ8.4 | โ ๏ธ 8.1โ8.4 (narrow) |
| Temperament | peaceful | peaceful | โ Compatible |
| Adult Size | 4 in | 3.5 in | โ Similar |
| Min. Group | 3+ | 3+ | See below |
| Min. Tank Size | 55 gallons (for both species) | โ | |
Compatibility Positives
Incompatibility Reasons
Species Profiles
Molly โ Poecilia sphenops
Hardy livebearers that prefer alkaline, hard water โ sometimes slightly brackish. Prolific breeders; peaceful community fish.
Pajama Cardinalfish โ Sphaeramia nematoptera
The Pajama Cardinalfish is a popular, beginner-friendly fish that can add a splash of color to your aquarium. They are generally peaceful and can be kept in a community tank. With moderate activity levels and a preference for undisturbed swimming spaces, they require a well-maintained water quality and a spacious tank.
Frequently Asked Questions
Can Molly live with Pajama Cardinalfish?
Generally not recommended. Molly and Pajama Cardinalfish are generally not recommended to be housed together. One of these is a marine species and the other is not; they cannot share one aquarium. Their usable pH overlap is narrow and requires stable, tested water. Review the behavior and water details before deciding whether to attempt the pairing.
What tank size do I need for Molly and Pajama Cardinalfish together?
A minimum of 55 gallons is recommended for keeping Molly and Pajama Cardinalfish together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Molly and Pajama Cardinalfish?
72โ82ยฐF โ inside Molly's 72โ82ยฐF and Pajama Cardinalfish's 72โ82ยฐF.
Is a Molly aggressive toward a Pajama Cardinalfish?
Molly is peaceful and Pajama Cardinalfish is peaceful. No major aggression issues are expected between these species.
Related Compatibility Guides
Tank Size for Molly and Pajama Cardinalfish
Use the scenario that matches the actual group sizes and temperament you plan to keep.
| Scenario | Tank | When it applies |
|---|---|---|
| Minimum viable | 55 gal | Only for the recommended minimum groups, mature filtration, and close monitoring. |
| Recommended community | 75 gal | Adds territory, swimming room, and a safer buffer for behavior. |
| Low-conflict setup | 125 gal | Best when keeping larger schools or reducing territorial pressure. |