๐Ÿ  Fish Compatibility Guide

Can Black Ghost Knifefish and Serpae Tetra 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 Ghost Knifefish and Serpae Tetra Compatibility Overview

Black Ghost Knifefish and Serpae Tetra are generally not recommended to be housed together. The adult size gap creates a meaningful predation risk. Both are semi, so give them a larger, well-planted tank and watch how they settle in. Review the behavior and water details before deciding whether to attempt the pairing.

Compatibility factors for Black Ghost Knifefish and Serpae Tetra
FactorBlack Ghost KnifefishSerpae TetraVerdict
Temperature73โ€“82ยฐF68โ€“82ยฐFโœ… 73โ€“82ยฐF
pH Range6.0โ€“8.05.0โ€“7.5โœ… 6.0โ€“7.5
Temperamentsemisemiโš ๏ธ Monitor
Adult Size18.0 in1.6 inโŒ 11ร— difference
Min. Group1+10+See below
Min. Tank Size100 gallons (for both species)โ€”

Compatibility Positives

A stable shared temperature range is available.
Their pH requirements overlap.

Incompatibility Reasons

The adult size gap creates a meaningful predation risk.
Both are semi, so give them a larger, well-planted tank and watch how they settle in.

Species Profiles

Black Ghost Knifefish โ€” Apteronotus albifrons

Black Ghost Knifefish and Serpae Tetra compatibility โ€” Black Ghost Knifefish

The Black Ghost Knifefish is a unique and elegant addition to the aquarium. With a lifespan of 5-8 years, it requires a minimum tank size of 200 liters. It is a solitary fish with a low aggression level and moderate activity. Its slender body and silver-blue coloration make it a captivating sight.

โ†’ Full Black Ghost Knifefish care guide

Serpae Tetra โ€” Hyphessobrycon eques

Black Ghost Knifefish and Serpae Tetra compatibility โ€” Serpae Tetra

The Serpae Tetra is a popular freshwater fish known for its vibrant coloration and peaceful nature. It is well-suited for community tanks and can be a great addition to any aquarium. With its moderate activity level and easy care requirements, it is a suitable choice for beginners and experienced aquarists alike.

โ†’ Full Serpae Tetra care guide

Frequently Asked Questions

Can Black Ghost Knifefish live with Serpae Tetra?

Generally not recommended. Black Ghost Knifefish and Serpae Tetra are generally not recommended to be housed together. The adult size gap creates a meaningful predation risk. Both are semi, so give them a larger, well-planted tank and watch how they settle in. Review the behavior and water details before deciding whether to attempt the pairing.

What tank size do I need for Black Ghost Knifefish and Serpae Tetra together?

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

What temperature suits both Black Ghost Knifefish and Serpae Tetra?

73โ€“82ยฐF โ€” inside Black Ghost Knifefish's 73โ€“82ยฐF and Serpae Tetra's 68โ€“82ยฐF.

Is a Black Ghost Knifefish aggressive toward a Serpae Tetra?

The adult size gap creates a meaningful predation risk.

Related Compatibility Guides

Tank Size for Black Ghost Knifefish and Serpae Tetra

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.