Compatibility Overview
Black Ruby Barb and Rainbow Shark 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 | Black Ruby Barb | Rainbow Shark | Verdict |
|---|---|---|---|
| Temperature | 72–79°F | 72–79°F | ✅ 72–79°F |
| pH Range | 6.5–7.5 | 6.5–7.5 | ✅ 6.5–7.5 |
| Temperament | aggressive | semi | ❌ Risk |
| Adult Size | 1.6 in | 6 in | ⚠️ 3.8× difference |
| Min. Group | 6+ | 1+ | See below |
| Min. Tank Size | 75 gallons (for both species) | — | |
✅ Compatibility Positives
❌ Incompatibility Reasons
Species Profiles
Black Ruby Barb — Aquarium species
The Black Ruby Barb is a vibrant, active species suitable for beginners. It requires a spacious tank and a school of its own kind to thrive. Its striking colors and lively nature make it a popular choice.
→ Full Black Ruby Barb care guide
Rainbow Shark — Epalzeorhynchos frenatum
Active bottom dweller that becomes territorial at maturity. One per tank; avoid other shark-like or bottom-dwelling species.
Frequently Asked Questions
Can Black Ruby Barb live with Rainbow Shark?
Generally not recommended. Black Ruby Barb and Rainbow Shark 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 Black Ruby Barb and Rainbow Shark together?
A minimum of 75 gallons is recommended for keeping Black Ruby Barb and Rainbow Shark together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Black Ruby Barb and Rainbow Shark?
72–79°F
Is a Black Ruby Barb aggressive toward a Rainbow Shark?
Black Ruby Barb is aggressive and Rainbow Shark is semi. The adult size gap creates a meaningful predation risk.
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 | 100/100 |
| Temperament | 25/100 |
| Adult Size | 38/100 |
| Swim Zone | 68/100 |
| 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 | 75 gal | Only for the recommended minimum groups, mature filtration, and close monitoring. |
| Recommended community | 125 gal | Adds territory, swimming room, and a safer buffer for behavior. |
| Low-conflict setup | 150 gal | Best when keeping larger schools or reducing territorial pressure. |