Swordtail and Watchman Goby Compatibility Overview
Swordtail and Watchman Goby 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. Their usable pH overlap is narrow and requires stable, tested water. Review the behavior and water details before deciding whether to attempt the pairing.
| Factor | Swordtail | Watchman Goby | Verdict |
|---|---|---|---|
| Temperature | 65โ80ยฐF | 72โ82ยฐF | โ 72โ80ยฐF |
| pH Range | 7.0โ8.3 | 8.1โ8.4 | โ ๏ธ 8.1โ8.3 (narrow) |
| Temperament | peaceful | peaceful | โ Compatible |
| Adult Size | 5 in | 4.0 in | โ Similar |
| Min. Group | 3+ | 1+ | See below |
| Min. Tank Size | 55 gallons (for both species) | โ | |
Compatibility Positives
Incompatibility Reasons
Species Profiles
Swordtail โ Xiphophorus hellerii
Hardy livebearer with a distinctive elongated lower tail fin in males. Peaceful community fish that tolerate a wide temperature range.
Watchman Goby โ Cryptocentrus cinctus
The Watchman Goby is a peaceful and colorful addition to the marine aquarium. It is known for its slender body and distinctive yellow and dark spot pattern. These gobies are often found in pairs or small groups and require a well-maintained saltwater tank with plenty of hiding spots. With proper care, they can thrive for several years.
Frequently Asked Questions
Can Swordtail live with Watchman Goby?
Generally not recommended. Swordtail and Watchman Goby 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. Their usable pH overlap is narrow and requires stable, tested water. Review the behavior and water details before deciding whether to attempt the pairing.
What tank size do I need for Swordtail and Watchman Goby together?
A minimum of 55 gallons is recommended for keeping Swordtail and Watchman Goby together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Swordtail and Watchman Goby?
72โ80ยฐF โ inside Swordtail's 65โ80ยฐF and Watchman Goby's 72โ82ยฐF.
Is a Swordtail aggressive toward a Watchman Goby?
Swordtail is peaceful and Watchman Goby is peaceful. No major aggression issues are expected between these species.
Related Compatibility Guides
Tank Size for Swordtail and Watchman Goby
Use the scenario that matches the actual group sizes and temperament you plan to keep.
| Scenario | Tank | When it applies |
|---|---|---|
| Minimum viable | 55 gal | Only for the recommended minimum groups, mature filtration, and close monitoring. |
| Recommended community | 75 gal | Adds territory, swimming room, and a safer buffer for behavior. |
| Low-conflict setup | 125 gal | Best when keeping larger schools or reducing territorial pressure. |