Compatibility Overview
Pajama Cardinalfish and Yoyo Loach are generally not recommended to be housed together. The issues listed above — whether water parameter incompatibility, predation risk, or aggression — create conditions where one or both fish are likely to suffer harm or chronic stress.
| Factor | Pajama Cardinalfish | Yoyo Loach | Verdict |
|---|---|---|---|
| Temperature | 72–82°F | 72–79°F | ✅ 72–79°F |
| pH Range | 8.0–8.3 | 6.5–7.5 | ❌ No overlap |
| Temperament | semi | semi | ⚠️ Monitor |
| Adult Size | 1.6 in | 2.0 in | ✅ Similar |
| Min. Group | 1+ | 1+ | See below |
| Min. Tank Size | 20 gallons (for both species) | — | |
✅ Compatibility Positives
❌ Incompatibility Reasons
Species Profiles
Pajama Cardinalfish — Aquarium species
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.
→ Full Pajama Cardinalfish care guide
Yoyo Loach — Aquarium species
The Yoyo Loach is a popular freshwater species known for its striking black and white coloration. They are peaceful and make great community fish, though they may be shy and require a well-established tank with ample hiding spots. These loaches are moderately active and do well in a tank with plenty of room to swim. With proper care, they can live up to 5 ye
Frequently Asked Questions
Can Pajama Cardinalfish live with Yoyo Loach?
Generally not recommended. Pajama Cardinalfish and Yoyo Loach are generally not recommended to be housed together. The issues listed above — whether water parameter incompatibility, predation risk, or aggression — create conditions where one or both fish are likely to suffer harm or chronic stress.
What tank size do I need for Pajama Cardinalfish and Yoyo Loach together?
A minimum of 20 gallons is recommended for keeping Pajama Cardinalfish and Yoyo Loach together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Pajama Cardinalfish and Yoyo Loach?
72–79°F
Is a Pajama Cardinalfish aggressive toward a Yoyo Loach?
Pajama Cardinalfish is semi and Yoyo Loach is semi. These animals require different water types and cannot share one aquarium.
Related Compatibility Guides
Compatibility score breakdown
The overall score is weighted across water chemistry, behavior, adult size, swimming zone, and social needs. A score is a planning aid—not a guarantee for individual fish.
| Factor | Score |
|---|---|
| Temperature | 100/100 |
| Ph | 0/100 |
| Temperament | 62/100 |
| Adult Size | 100/100 |
| Swim Zone | 92/100 |
| Social Needs | 92/100 |
Tank size scenarios
Use the scenario that matches the actual group sizes and temperament you plan to keep.
| Scenario | Tank | When it applies |
|---|---|---|
| Minimum viable | 26 gal | Only for the recommended minimum groups, mature filtration, and close monitoring. |
| Recommended community | 40 gal | Adds territory, swimming room, and a safer buffer for behavior. |
| Low-conflict setup | 55 gal | Best when keeping larger schools or reducing territorial pressure. |