Compatibility Overview
Blue Tang and Julii Cory 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 | Blue Tang | Julii Cory | Verdict |
|---|---|---|---|
| Temperature | 75–81°F | 72–79°F | ✅ 75–79°F |
| pH Range | 8.1–8.4 | 6.0–7.0 | ❌ No overlap |
| Temperament | semi | semi | ⚠️ Monitor |
| Adult Size | 5.9 in | 1.2 in | ❌ 5× difference |
| Min. Group | 1+ | 1+ | See below |
| Min. Tank Size | 55 gallons (for both species) | — | |
✅ Compatibility Positives
❌ Incompatibility Reasons
Species Profiles
Blue Tang — Aquarium species
The Blue Tang is a popular saltwater fish known for its vibrant blue color and yellow stripes. These fish are generally peaceful and can be kept in a community tank with other non-aggressive species. They require a well-maintained, spacious tank with plenty of swimming space and hiding spots. Regular water changes and proper nutrition are essential for their
Julii Cory — Aquarium species
The Julii Cory is a popular, peaceful bottom-dweller that thrives in community tanks. With a lifespan of up to 5 years, they are suitable for beginners and experienced aquarists alike. These fish are known for their dark brown coloration with distinctive white spots and a slender, flat body shape. They are moderately active and prefer a well-planted tank wit
Frequently Asked Questions
Can Blue Tang live with Julii Cory?
Generally not recommended. Blue Tang and Julii Cory 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 Blue Tang and Julii Cory together?
A minimum of 55 gallons is recommended for keeping Blue Tang and Julii Cory together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Blue Tang and Julii Cory?
75–79°F
Is a Blue Tang aggressive toward a Julii Cory?
Blue Tang is semi and Julii Cory 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 | 67/100 |
| Ph | 0/100 |
| Temperament | 62/100 |
| Adult Size | 38/100 |
| 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 | 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 | 100 gal | Best when keeping larger schools or reducing territorial pressure. |