Compatibility Overview
Clown Pleco and Harlequin Rasbora 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 | Clown Pleco | Harlequin Rasbora | Verdict |
|---|---|---|---|
| Temperature | 72–79°F | 72–81°F | ✅ 72–79°F |
| pH Range | 6.0–7.0 | 5.5–7.5 | ✅ 6.0–7.0 |
| Temperament | semi | peaceful | ⚠️ Monitor |
| Adult Size | 7.9 in | 1.75 in | ❌ 5× difference |
| Min. Group | 1+ | 8+ | See below |
| Min. Tank Size | 100 gallons (for both species) | — | |
✅ Compatibility Positives
❌ Incompatibility Reasons
Species Profiles
Clown Pleco — Aquarium species
The Clown Pleco is a popular freshwater fish known for its dark brown body with light spots and long, flattened body shape. They are peaceful and make great community fish for beginners. These plecos are moderate in activity level and prefer a tank with plenty of hiding spots.
Harlequin Rasbora — Trigonostigma heteromorpha
Active mid-level schooling fish with a distinctive black triangular patch. One of the best all-around community tank fish.
Frequently Asked Questions
Can Clown Pleco live with Harlequin Rasbora?
Generally not recommended. Clown Pleco and Harlequin Rasbora 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 Clown Pleco and Harlequin Rasbora together?
A minimum of 100 gallons is recommended for keeping Clown Pleco and Harlequin Rasbora together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Clown Pleco and Harlequin Rasbora?
72–79°F
Is a Clown Pleco aggressive toward a Harlequin Rasbora?
Clown Pleco is semi and Harlequin Rasbora is peaceful. 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 | 75/100 |
| 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 | 100 gal | Only for the recommended minimum groups, mature filtration, and close monitoring. |
| Recommended community | 150 gal | Adds territory, swimming room, and a safer buffer for behavior. |
| Low-conflict setup | 220 gal | Best when keeping larger schools or reducing territorial pressure. |