๐Ÿ  Fish Compatibility Guide

Can Black Phantom Tetra and Clown Knifefish 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 Phantom Tetra and Clown Knifefish Compatibility Overview

Black Phantom Tetra and Clown Knifefish are generally not recommended to be housed together. 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. Review the behavior and water details before deciding whether to attempt the pairing.

Compatibility factors for Black Phantom Tetra and Clown Knifefish
FactorBlack Phantom TetraClown KnifefishVerdict
Temperature68โ€“82ยฐF68โ€“82ยฐFโœ… 68โ€“82ยฐF
pH Range5.0โ€“7.06.0โ€“8.0โœ… 6.0โ€“7.0
TemperamentpeacefulaggressiveโŒ Risk
Adult Size1.4 in39.4 inโŒ 28ร— difference
Min. Group8+1+See below
Min. Tank Size100 gallons (for both species)โ€”

Compatibility Positives

A stable shared temperature range is available.

Incompatibility Reasons

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.
Black Phantom Tetra is peaceful and Clown Knifefish is aggressive. Expect chasing and fin damage unless the tank is oversized, heavily planted, and watched closely.

Species Profiles

Black Phantom Tetra โ€” Hyphessobrycon megalopterus

Black Phantom Tetra and Clown Knifefish compatibility โ€” Black Phantom Tetra

The Black Phantom Tetra is a popular freshwater fish known for its striking black and silver coloration. It is generally peaceful and can be kept in a community tank with other non-aggressive species. They require a well-maintained tank with a moderate water flow and a good cover of plants.

โ†’ Full Black Phantom Tetra care guide

Clown Knifefish โ€” Chitala ornata

Black Phantom Tetra and Clown Knifefish compatibility โ€” Clown Knifefish

The Clown Knifefish is a unique and visually striking species known for its slender body and distinctive coloration. It is a solitary fish that requires a spacious tank to thrive. With a moderate activity level and low aggression, it can be a suitable addition to a community tank with similarly peaceful species.

โ†’ Full Clown Knifefish care guide

Frequently Asked Questions

Can Black Phantom Tetra live with Clown Knifefish?

Generally not recommended. Black Phantom Tetra and Clown Knifefish are generally not recommended to be housed together. 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. Review the behavior and water details before deciding whether to attempt the pairing.

What tank size do I need for Black Phantom Tetra and Clown Knifefish together?

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

What temperature suits both Black Phantom Tetra and Clown Knifefish?

68โ€“82ยฐF โ€” inside Black Phantom Tetra's 68โ€“82ยฐF and Clown Knifefish's 68โ€“82ยฐF.

Is a Black Phantom Tetra aggressive toward a Clown Knifefish?

The adult size gap creates a meaningful predation risk.

Related Compatibility Guides

Tank Size for Black Phantom Tetra and Clown Knifefish

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

ScenarioTankWhen it applies
Minimum viable300 galOnly for the recommended minimum groups, mature filtration, and close monitoring.
Recommended community450 galAdds territory, swimming room, and a safer buffer for behavior.
Low-conflict setup550 galBest when keeping larger schools or reducing territorial pressure.