🐠 Fish Compatibility Guide

Can Clown Loach Live With Harlequin Rasbora?

⚠️ Use Caution — Compatibility Score: 55/100
55/100 — Use Caution

Compatibility Overview

Clown Loach and Harlequin Rasbora can potentially coexist, but the combination requires careful attention. Some combination of water parameter differences, size mismatch, or temperament issues make this pair challenging. A larger tank (minimum 100 gallons), dense planting, and close monitoring are essential.

FactorClown LoachHarlequin RasboraVerdict
Temperature77–86°F72–81°F✅ 77–81°F
pH Range6.0–7.55.5–7.5✅ 6.0–7.5
Temperamentpeacefulpeaceful✅ Compatible
Adult Size12 in1.75 in❌ 7× difference
Min. Group5+8+See below
Min. Tank Size100 gallons (for both species)

✅ Compatibility Positives

pH ranges are compatible: workable range is 6.0–7.5.
Both species are peaceful — low aggression risk.
Both species are schooling fish — keep Clown Loach in groups of 5+ and Harlequin Rasbora in groups of 8+.

⚠️ Caution Points

⚠️Narrow temperature overlap (77–81°F) — keeping the tank at exactly 78–80°F is needed for both species.
⚠️Large size difference: Clown Loach (12 in) may predate on Harlequin Rasbora (1.75 in).

Species Profiles

Clown Loach — Chromobotia macracanthus

Striking striped loach that grows very large. Peaceful with fish but will eat shrimp, snails and tiny fish.

→ Full Clown Loach care guide

Harlequin Rasbora — Trigonostigma heteromorpha

Active mid-level schooling fish with a distinctive black triangular patch. One of the best all-around community tank fish.

→ Full Harlequin Rasbora care guide

Frequently Asked Questions

Can Clown Loach live with Harlequin Rasbora?

With significant caution and a larger tank. Clown Loach and Harlequin Rasbora can potentially coexist, but the combination requires careful attention. Some combination of water parameter differences, size mismatch, or temperament issues make this pair challenging. A larger tank (minimum 100 gallons), dense planting, and close monitoring are essential.

What tank size do I need for Clown Loach and Harlequin Rasbora together?

A minimum of 100 gallons is recommended for keeping Clown Loach and Harlequin Rasbora together. A larger tank improves water stability and reduces territorial conflict.

What temperature suits both Clown Loach and Harlequin Rasbora?

77–81°F

Is a Clown Loach aggressive toward a Harlequin Rasbora?

Clown Loach is peaceful and Harlequin Rasbora is peaceful. Narrow temperature overlap (77–81°F) — keeping the tank at exactly 78–80°F is needed for both species.