Cardinal Tetra and Watchman Goby Compatibility Overview
Cardinal Tetra 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 pH ranges do not meet: Cardinal Tetra wants 4.5โ7.0 and Watchman Goby wants 8.1โ8.4. Review the behavior and water details before deciding whether to attempt the pairing.
| Factor | Cardinal Tetra | Watchman Goby | Verdict |
|---|---|---|---|
| Temperature | 73โ82ยฐF | 72โ82ยฐF | โ 73โ82ยฐF |
| pH Range | 4.5โ7.0 | 8.1โ8.4 | โ No overlap |
| Temperament | peaceful | peaceful | โ Compatible |
| Adult Size | 1.5 in | 4.0 in | โ ๏ธ 2.7ร difference |
| Min. Group | 6+ | 1+ | See below |
| Min. Tank Size | 55 gallons (for both species) | โ | |
Compatibility Positives
Incompatibility Reasons
Species Profiles
Cardinal Tetra โ Paracheirodon axelrodi
Brilliant red-and-blue schooling fish from the Rio Negro. Prefers soft, acidic, warm water โ a natural companion for discus.
โ Full Cardinal Tetra care guide
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 Cardinal Tetra live with Watchman Goby?
Generally not recommended. Cardinal Tetra 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 pH ranges do not meet: Cardinal Tetra wants 4.5โ7.0 and Watchman Goby wants 8.1โ8.4. Review the behavior and water details before deciding whether to attempt the pairing.
What tank size do I need for Cardinal Tetra and Watchman Goby together?
A minimum of 55 gallons is recommended for keeping Cardinal Tetra and Watchman Goby together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Cardinal Tetra and Watchman Goby?
73โ82ยฐF โ inside Cardinal Tetra's 73โ82ยฐF and Watchman Goby's 72โ82ยฐF.
Is a Cardinal Tetra aggressive toward a Watchman Goby?
Cardinal Tetra is peaceful and Watchman Goby is peaceful. No major aggression issues are expected between these species.
Related Compatibility Guides
Tank Size for Cardinal Tetra 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. |