Can Johanni Cichlid live with Harlequin Rasbora?
Troubleshooting community setups: see the compatibility result using temperature, pH, GH/KH, adult size, behavior, schooling needs, and predator/prey rules.
AvoidJohanni Cichlid and Harlequin Rasbora compatibility verdict
Short answer: No, this pairing should usually be avoided. Plan for at least 55 gallons before adjusting for group size, filtration, and aquascape layout.
- aggression_riskAggression or territorial behavior needs extra space, cover, and careful observation.
- biotope_mismatchMalawi mbuna are territorial hard-water cichlids, not peaceful community fish; this pairing mixes incompatible behavior and water expectations.
redNo, avoid this pairing
Data confidence: high
- aggression_riskAggression or territorial behavior needs extra space, cover, and careful observation.
- biotope_mismatchMalawi mbuna are territorial hard-water cichlids, not peaceful community fish; this pairing mixes incompatible behavior and water expectations.
- ph_range_conflictAggression or territorial behavior needs extra space, cover, and careful observation.
- gh_kh_mismatchAggression or territorial behavior needs extra space, cover, and careful observation.
Verified sources: Mbuna overview | Labidochromis caeruleus overview
johanni cichlid | harlequin rasbora | johanni cichlid | harlequin rasbora
Schooling and group-size requirements
This verdict assumes normal social groups, not one stressed specimen. Johanni Cichlid should be planned at 4+; Harlequin Rasbora should be planned at 6+ before judging long-term compatibility.
Real-World Experience
Textbook score vs observed behavior
A compatibility score checks adult size, temperature, pH, hardness, temperament, and tank volume. Real tanks add variables the score cannot see directly: feeding aggression, cave ownership, plant cover, and whether fish can constantly see each other.
Line-of-sight and swim-zone pressure
Johanni Cichlid and Harlequin Rasbora use different swim zones, but feeding time and open sightlines can still change behavior. Start with at least 55 gallons, then use hardscape, tall plants, and separated feeding zones to reduce chasing before it becomes a pattern.
Water parameter comparison
Johanni Cichlid temperature72-82F
Harlequin Rasbora temperature72-80F
Johanni Cichlid pH7.5-8.8
Harlequin Rasbora pH6-7.8
Johanni Cichlid GH10-20 dGH
Harlequin Rasbora GH2-12 dGH
Minimum tank55 gal
Last updated2026-06-11
Confidence: high. Aggression, predator/prey, shrimp risk, schooling, and tank size rules are evaluated from curated freshwater attributes.
Troubleshooting aggression between Johanni Cichlid and Harlequin Rasbora
Problems can happen even when the gallon number is technically adequate. Check feeding order, repeated access to the same cave or plant mass, school size, and whether the aquascape gives either fish a direct line of sight across the whole tank.
Bottom dweller competition between Johanni Cichlid and Harlequin Rasbora
If either species uses the lower half of the tank, add more broken sightlines and avoid placing all food in one corner. Bottom pressure is more about usable floor space than total water volume.
How to break line-of-sight to reduce aggression
Use tall plants, rock piles, driftwood, and separate feeding stations so a dominant fish cannot patrol one open lane from end to end.