๐Ÿ  Fish Compatibility Guide

Can Molly and Red Eye Tetra Live Together?

Updated September 23, 2026 ยท FishCare AI Editorial Team

โœ… Compatible โ€” Compatibility Score: 82/100
82/100 โ€” Compatible

Molly and Red Eye Tetra Compatibility Overview

Molly and Red Eye Tetra can generally share an aquarium with appropriate planning. Both species prefer overlapping temperature and pH ranges. Molly is peaceful and Red Eye Tetra is semi, so give them room and cover rather than assuming they will ignore each other. A minimum 55-gallon tank is recommended to provide adequate territory and water volume for both species.

Compatibility factors for Molly and Red Eye Tetra
FactorMollyRed Eye TetraVerdict
Temperature72โ€“82ยฐF72โ€“79ยฐFโœ… 72โ€“79ยฐF
pH Range7.5โ€“8.56.0โ€“8.0โš ๏ธ 7.5โ€“8.0 (narrow)
Temperamentpeacefulsemiโš ๏ธ Monitor
Adult Size4 in2.8 inโœ… Similar
Min. Group3+6+See below
Min. Tank Size55 gallons (for both species)โ€”

Compatibility Positives

A stable shared temperature range is available.
Temperament risk is relatively low when normal group sizes are maintained.

Caution Points

Their pH ranges overlap only partly, so aim for the shared band and keep it steady.

Species Profiles

Molly โ€” Poecilia sphenops

Molly and Red Eye Tetra compatibility โ€” Molly

Hardy livebearers that prefer alkaline, hard water โ€” sometimes slightly brackish. Prolific breeders; peaceful community fish.

โ†’ Full Molly care guide

Red Eye Tetra โ€” Moenkhausia sanctaefilomenae

Molly and Red Eye Tetra compatibility โ€” Red Eye Tetra

The Red Eye Tetra is a popular freshwater fish known for its vibrant red eyes and sleek, silver body. They are generally peaceful and can be kept in a community tank with other non-aggressive species. Their moderate activity level makes them suitable for a variety of aquarium setups. With proper care, they can live up to 5 years.

โ†’ Full Red Eye Tetra care guide

Frequently Asked Questions

Can Molly live with Red Eye Tetra?

Yes, in a well-planned setup. Molly and Red Eye Tetra can generally share an aquarium with appropriate planning. Both species prefer overlapping temperature and pH ranges. Molly is peaceful and Red Eye Tetra is semi, so give them room and cover rather than assuming they will ignore each other. A minimum 55-gallon tank is recommended to provide adequate territory and water volume for both species.

What tank size do I need for Molly and Red Eye Tetra together?

A minimum of 55 gallons is recommended for keeping Molly and Red Eye Tetra together. A larger tank improves water stability and reduces territorial conflict.

What temperature suits both Molly and Red Eye Tetra?

72โ€“79ยฐF โ€” inside Molly's 72โ€“82ยฐF and Red Eye Tetra's 72โ€“79ยฐF.

Is a Molly aggressive toward a Red Eye Tetra?

Molly is peaceful and Red Eye Tetra is semi. No major aggression issues are expected between these species.

Related Compatibility Guides

Tank Size for Molly and Red Eye Tetra

Use the scenario that matches the actual group sizes and temperament you plan to keep.

ScenarioTankWhen it applies
Minimum viable55 galOnly for the recommended minimum groups, mature filtration, and close monitoring.
Recommended community75 galAdds territory, swimming room, and a safer buffer for behavior.
Low-conflict setup125 galBest when keeping larger schools or reducing territorial pressure.