Otocinclus and Pajama Cardinalfish Compatibility Overview
Otocinclus 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 pH ranges do not meet: Otocinclus wants 6.0โ7.5 and Pajama Cardinalfish wants 8.1โ8.4. Review the behavior and water details before deciding whether to attempt the pairing.
| Factor | Otocinclus | Pajama Cardinalfish | Verdict |
|---|---|---|---|
| Temperature | 72โ82ยฐF | 72โ82ยฐF | โ 72โ82ยฐF |
| pH Range | 6.0โ7.5 | 8.1โ8.4 | โ No overlap |
| Temperament | peaceful | peaceful | โ Compatible |
| Adult Size | 1.5 in | 3.5 in | โ ๏ธ 2.3ร difference |
| Min. Group | 4+ | 3+ | See below |
| Min. Tank Size | 40 gallons (for both species) | โ | |
Compatibility Positives
Incompatibility Reasons
Species Profiles
Otocinclus โ Otocinclus spp.
Tiny algae-eating catfish that are peaceful with all species. Need established algae growth and biofilm; sensitive to ammonia.
โ Full Otocinclus care guide
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 Otocinclus live with Pajama Cardinalfish?
Generally not recommended. Otocinclus 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 pH ranges do not meet: Otocinclus wants 6.0โ7.5 and Pajama Cardinalfish wants 8.1โ8.4. Review the behavior and water details before deciding whether to attempt the pairing.
What tank size do I need for Otocinclus and Pajama Cardinalfish together?
A minimum of 40 gallons is recommended for keeping Otocinclus and Pajama Cardinalfish together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Otocinclus and Pajama Cardinalfish?
72โ82ยฐF โ inside Otocinclus's 72โ82ยฐF and Pajama Cardinalfish's 72โ82ยฐF.
Is a Otocinclus aggressive toward a Pajama Cardinalfish?
Otocinclus is peaceful and Pajama Cardinalfish is peaceful. No major aggression issues are expected between these species.
Related Compatibility Guides
Tank Size for Otocinclus 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 | 40 gal | Only for the recommended minimum groups, mature filtration, and close monitoring. |
| Recommended community | 55 gal | Adds territory, swimming room, and a safer buffer for behavior. |
| Low-conflict setup | 90 gal | Best when keeping larger schools or reducing territorial pressure. |