๐Ÿ  Fish Compatibility Guide

Can Black Neon Tetra and Koi Live Together?

Updated September 23, 2026 ยท FishCare AI Editorial Team

โŒ Not Compatible โ€” Compatibility Score: 32/100
32/100 โ€” Not Compatible

Black Neon Tetra and Koi Compatibility Overview

Black Neon Tetra and Koi are generally not recommended to be housed together. Koi is a cool-water fish and Black Neon Tetra is tropical, so the usable temperature range decides this pairing. The adult size gap creates a meaningful predation risk. Review the behavior and water details before deciding whether to attempt the pairing.

Compatibility factors for Black Neon Tetra and Koi
FactorBlack Neon TetraKoiVerdict
Temperature68โ€“82ยฐF50โ€“75ยฐFโœ… 68โ€“75ยฐF
pH Range5.0โ€“7.57.0โ€“8.5โš ๏ธ 7.0โ€“7.5 (narrow)
Temperamentpeacefulpeacefulโœ… Compatible
Adult Size1.4 in24 inโŒ 17ร— difference
Min. Group8+2+See below
Min. Tank Size100 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.

Incompatibility Reasons

Koi is a cool-water fish and Black Neon Tetra is tropical, so the usable temperature range decides this pairing.
The adult size gap creates a meaningful predation risk.
Their pH ranges overlap only partly, so aim for the shared band and keep it steady.

Species Profiles

Black Neon Tetra โ€” Hyphessobrycon herbertaxelrodi

Black Neon Tetra and Koi compatibility โ€” Black Neon Tetra

The Black Neon Tetra is a popular freshwater species known for its vibrant colors and peaceful temperament. It is an excellent addition to community tanks, thriving in groups of 6 or more. These tetras require a well-maintained aquarium with a flowing current and plenty of swimming space. With proper care, they can live up to 5 years.

โ†’ Full Black Neon Tetra care guide

Koi โ€” Cyprinus rubrofuscus

Black Neon Tetra and Koi compatibility โ€” Koi

Large pond fish that require hundreds of gallons and cool water. Will eat any fish small enough to fit in their mouth.

โ†’ Full Koi care guide

Frequently Asked Questions

Can Black Neon Tetra live with Koi?

Generally not recommended. Black Neon Tetra and Koi are generally not recommended to be housed together. Koi is a cool-water fish and Black Neon Tetra is tropical, so the usable temperature range decides this pairing. The adult size gap creates a meaningful predation risk. Review the behavior and water details before deciding whether to attempt the pairing.

What tank size do I need for Black Neon Tetra and Koi together?

A minimum of 100 gallons is recommended for keeping Black Neon Tetra and Koi together. A larger tank improves water stability and reduces territorial conflict.

What temperature suits both Black Neon Tetra and Koi?

68โ€“75ยฐF โ€” inside Black Neon Tetra's 68โ€“82ยฐF and Koi's 50โ€“75ยฐF.

Is a Black Neon Tetra aggressive toward a Koi?

The adult size gap creates a meaningful predation risk.

Related Compatibility Guides

Tank Size for Black Neon Tetra and Koi

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

ScenarioTankWhen it applies
Minimum viable100 galOnly for the recommended minimum groups, mature filtration, and close monitoring.
Recommended community150 galAdds territory, swimming room, and a safer buffer for behavior.
Low-conflict setup220 galBest when keeping larger schools or reducing territorial pressure.