๐Ÿ  Fish Compatibility Guide

Can Clown Knifefish and Royal Gramma Live Together?

Updated September 23, 2026 ยท FishCare AI Editorial Team

โŒ Not Compatible โ€” Compatibility Score: 0/100
0/100 โ€” Not Compatible

Clown Knifefish and Royal Gramma Compatibility Overview

Clown Knifefish and Royal Gramma are generally not recommended to be housed together. One of these is a marine species and the other is not; they cannot share one aquarium. 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 Clown Knifefish and Royal Gramma
FactorClown KnifefishRoyal GrammaVerdict
Temperature68โ€“82ยฐF72โ€“82ยฐFโœ… 72โ€“82ยฐF
pH Range6.0โ€“8.08.1โ€“8.4โŒ No overlap
TemperamentaggressivesemiโŒ Risk
Adult Size39.4 in3.0 inโŒ 13ร— difference
Min. Group1+1+See below
Min. Tank Size100 gallons (for both species)โ€”

Compatibility Positives

A stable shared temperature range is available.

Incompatibility Reasons

One of these is a marine species and the other is not; they cannot share one aquarium.
The adult size gap creates a meaningful predation risk.
Their pH ranges do not meet: Clown Knifefish wants 6.0โ€“8.0 and Royal Gramma wants 8.1โ€“8.4.
Clown Knifefish is aggressive and Royal Gramma is semi. Expect chasing and fin damage unless the tank is oversized, heavily planted, and watched closely.

Species Profiles

Clown Knifefish โ€” Chitala ornata

Clown Knifefish and Royal Gramma 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

Royal Gramma โ€” Gramma loreto

Clown Knifefish and Royal Gramma compatibility โ€” Royal Gramma

The Royal Gramma, known for its vibrant blue coloration, is a popular saltwater fish among beginners and experienced aquarists alike. It requires a well-maintained tank with plenty of swimming space and a moderate current. With a peaceful temperament and a relatively easy care routine, the Royal Gramma can be a great addition to a community tank.

โ†’ Full Royal Gramma care guide

Frequently Asked Questions

Can Clown Knifefish live with Royal Gramma?

Generally not recommended. Clown Knifefish and Royal Gramma are generally not recommended to be housed together. One of these is a marine species and the other is not; they cannot share one aquarium. 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 Clown Knifefish and Royal Gramma together?

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

What temperature suits both Clown Knifefish and Royal Gramma?

72โ€“82ยฐF โ€” inside Clown Knifefish's 68โ€“82ยฐF and Royal Gramma's 72โ€“82ยฐF.

Is a Clown Knifefish aggressive toward a Royal Gramma?

The adult size gap creates a meaningful predation risk.

Related Compatibility Guides

Tank Size for Clown Knifefish and Royal Gramma

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.