LogoAquarium Calculator
STATUS: INCOMPATIBLE ⬌ MATRIX CORRELATION INDEX

Can you keep Harlequin Rasbora and Knight Goby Fish together?

Algorithmically generated environmental and behavioral compatibility report.

Harlequin RasboraTrigonostigma heteromorpha
mid Layerpeaceful
incompatible
Knight Goby FishStigmatogobius sadanundio
bottom Layersemi-aggressive
INCOMPATIBLE

Algorithmic Assessment

Water acidity (pH) parameters clash. Harlequin Rasbora prefers a pH of 6-6.8, while Knight Goby Fish requires a pH of 7-8.5. There is no overlapping safe pH range.

Scientific Parameter Comparison

Cross-reference water chemistry, temperature range envelopes, and physical dimensions of Harlequin Rasbora and Knight Goby Fish.

Parameter MetricHarlequin RasboraKnight Goby FishCalculated Overlap
Temperature Range73°F – 80°F72°F – 82°F73°F – 80°F
pH Chemistry6.0 – 6.87.0 – 8.5No Overlap (Mismatch: 0.2)
Min. Tank Capacity10 Gallons30 Gallons30 Gallons (Minimum)
Aquatic Strata ZonemidbottomSeparated Layers
Adult Size (Max)1.8" (4 cm)3.5" (9 cm)Ratio: 1 : 2.0

⚠ Physiological Mismatch Report

Our stocking engine calculations indicate that putting these two species in the same tank causes acute physiological strain. Below are the calculated parameters that violate safe cohabitation ranges:

Acidity/pH Gap0.2 pH difference

Harlequin Rasbora thrives in pH 6-6.8, while Knight Goby Fish needs pH 7-8.5.

⚔️ Do Harlequin Rasbora and Knight Goby Fish Fight?

Environmental or structural requirements between these species clash too heavily to allow cohabitation. Water acidity (pH) parameters clash. Harlequin Rasbora prefers a pH of 6-6.8, while Knight Goby Fish requires a pH of 7-8.5. There is no overlapping safe pH range.

🍽️ Swimming Layers & Feeding Competition

To satisfy their dietary requirements, offer a varied feeding schedule. Sinking pellets or wafers are ideal for bottom dwellers, while floating flakes or micro-granules support mid and top dwellers. The Harlequin Rasbora occupies the mid layer, while the Knight Goby Fish occupies the bottom layer. This separation of swimming zones naturally minimizes direct interactions and reduces competition during feeding times.

📏 Size Difference & Predation Threat

Both species are closely matched in physical dimensions, with Harlequin Rasbora growing to 1.8 inches and Knight Goby Fish reaching 3.5 inches. This size balance ensures neither species holds a physical dominance advantage.

Safe Tankmate Alternatives for Harlequin Rasbora

Since the pairing between Harlequin Rasbora and Knight Goby Fish is flagged as incompatible, here are 3 peaceful community tankmates that share a flawless compatibility profile with Harlequin Rasbora and match similar water parameters:

Scientific NameTrigonostigma heteromorpha
Min Tank Capacity10G
Aggressionpeaceful
Temp Envelope73°F - 80°F
pH Chemistry6.0 - 6.8
Knight Goby Fishbottom Layer
Scientific NameStigmatogobius sadanundio
Min Tank Capacity30G
Aggressionsemi-aggressive
Temp Envelope72°F - 82°F
pH Chemistry7.0 - 8.5

Chemistry & Habitat Analysis

Temp Envelope
73°F - 80°F
Shared temperature bounds.
pH Chemistry
No Overlap
Acidity requirements clash.
Combined Min Tank
30 Gallons
Lowest acceptable volume.

Frequently Asked Questions: Harlequin Rasbora & Knight Goby Fish Compatibility

Are Harlequin Rasbora and Knight Goby Fish good tank mates?

Water acidity (pH) parameters clash. Harlequin Rasbora prefers a pH of 6-6.8, while Knight Goby Fish requires a pH of 7-8.5. There is no overlapping safe pH range.

Can you put Harlequin Rasbora and Knight Goby Fish in the same tank together?

Environmental or structural requirements between these species clash too heavily to allow cohabitation. Water acidity (pH) parameters clash. Harlequin Rasbora prefers a pH of 6-6.8, while Knight Goby Fish requires a pH of 7-8.5. There is no overlapping safe pH range.

What water temperature and pH parameters do Harlequin Rasbora and Knight Goby Fish need?

Both species require compatible parameters. Harlequin Rasbora needs a temperature of 73°F to 80°F and a pH of 6.0 to 6.8. Meanwhile, Knight Goby Fish needs a temperature of 72°F to 82°F and a pH of 7.0 to 8.5. Shared overlap range: 73°F–80°F temperature and No safe pH overlap overlap.

What is the minimum combined tank volume required to house Harlequin Rasbora and Knight Goby Fish?

To successfully house both species together, a baseline of 30 gallons is required. However, because the setup includes territorial behavior from Knight Goby Fish (semi-aggressive), we recommend an adjusted minimum tank volume of at least 40 gallons (adding a 10-gallon safety buffer) to establish separate visual boundaries and minimize stress.