Cryptocentrus cinctus (Yellow Watchman Goby / Yellow Prawn Goby)
• Small fish safe: ✅ Yes
• Small invert safe: ✅ Yes
• Coral safe: ✅ Yes
• Minimum tank size: 75L+ (preferably 100L+ for a bonded pair)
• Adult size: ~10 cm (4 inches)
• Diet: Carnivorous (marine pellets, frozen mysis/brine shrimp, and finely chopped seafood)
• Be aware of: Known for forming symbiotic relationships with pistol shrimp. Can be territorial towards other gobies but generally peaceful.
Yellow Watchman Goby (Cryptocentrus cinctus) – A Hardy and Entertaining Sand-Dweller
The Yellow Watchman Goby, also known as the Yellow Prawn Goby, is a popular and hardy bottom-dwelling fishthat brings both personality and functionality to a marine aquarium. It is best known for its mutualistic relationship with pistol shrimp, where the goby provides watchful protection while the shrimp digs and maintains their burrow. This species is an excellent addition to reef tanks, helping aerate the sand bed and creating a natural, dynamic interaction within the aquarium.
Appearance and Coloration
Yellow Watchman Gobies have a distinct and appealing appearance, featuring:
• A bright yellow to golden body, sometimes fading to a pale tan as they mature.
• Small iridescent blue spots scattered across their head, fins, and upper body.
• Large, expressive eyes and an almost grumpy-looking facial expression.
• A stocky build with rounded fins, allowing them to “hover” near their burrow.
• Males are typically larger with more pronounced dorsal fins, while females tend to be smaller and more slender.
Natural Habitat and Behaviour
Native to the Indo-Pacific region, Yellow Watchman Gobies inhabit lagoon reefs and sandy bottoms, where they:
• Live in burrows, often shared with pistol shrimp, forming a remarkable symbiotic partnership.
• Are highly territorial towards other bottom-dwelling fish, though peaceful with most other species.
• Prefer to perch near their burrow, observing their surroundings while retreating when threatened.
• Communicate with their shrimp partner through fin flicks and body movements, signaling danger or movement.
In captivity, they may dig their own burrow if a pistol shrimp is not present, though they thrive best when paired with a compatible shrimp species like the Randall’s Pistol Shrimp (Alpheus randalli).
Tank Requirements and Water Parameters
Yellow Watchman Gobies are easy to care for, but they require a sandy substrate and ample hiding places to feel secure.
• Minimum tank size: 75L+ (100L+ recommended for pairs or shrimp-goby partnerships)
• Temperature: 24–27°C (75–81°F)
• pH: 8.1–8.4
• Salinity: 1.020–1.025
• Water movement: Moderate (gentle currents preferred)
• Filtration: Good-quality filtration and regular water changes are essential for maintaining clean conditions.
A tank with fine sand and small rock caves will help the goby establish a burrow. Avoid coarse gravel, as it can injure their delicate undersides.
Diet and Feeding
Yellow Watchman Gobies are carnivorous, requiring a varied diet rich in protein.
Recommended foods include:
• Frozen mysis and brine shrimp – Their primary diet in captivity.
• High-quality marine pellets and flakes – Enriched formulas work best.
• Finely chopped seafood (shrimp, squid, or fish) – Occasional treats.
• Live foods (copepods, amphipods, or blackworms) – Enhances natural feeding behavior.
Feed once or twice daily, ensuring they receive enough food near their burrow, as they are not fast swimmers and may miss out during aggressive feeding sessions.
Compatibility and Tank Mates
Yellow Watchman Gobies are peaceful but can be territorial toward other bottom-dwellers. They pair well with:
✔ Pistol Shrimp (especially Randall’s Pistol Shrimp, Alpheus randalli) – Forms a fascinating symbiotic bond.
✔ Peaceful to semi-aggressive tank mates, such as Clownfish, Basslets, Fairy Wrasses, and Blennies.
✔ Reef-safe invertebrates, including shrimp, snails, and crabs.
Avoid housing with:
❌ Other Watchman Gobies or similar sand-dwelling species (e.g., Jawfish, other goby species) unless in a large tank.
❌ Overly aggressive fish, such as large wrasses, triggerfish, or aggressive dottybacks.
❌ Fast-feeding fish, as they may outcompete the goby for food.
If keeping a mated pair, introduce them at the same time to prevent territorial disputes.
Burrowing and Shrimp-Goby Symbiosis
Yellow Watchman Gobies naturally form symbiotic relationships with pistol shrimp, where:
• The shrimp digs and maintains a burrow, while the goby provides protection.
• The goby rests at the entrance, using its excellent eyesight to detect threats.
• If danger is near, the goby flicks its tail, signaling the shrimp to retreat inside.
If introducing a goby and shrimp together, ensure they are compatible, as not all pistol shrimp species will form a bond.
Health and Disease Considerations
Yellow Watchman Gobies are hardy, but they can be susceptible to:
• Marine Ich (Cryptocaryon irritans) – Stress-related; quarantine new fish before introduction.
• Bacterial infections – Usually caused by poor water quality or injuries from digging.
• Malnutrition – Ensure they get enough food, especially in competitive tanks.
Keeping stable water conditions, offering a high-protein diet, and ensuring a stress-free environment will keep them healthy.
Lifespan and Long-Term Care
With proper care, Yellow Watchman Gobies can live up to 5-8 years in captivity. Their hardy nature, fascinating shrimp symbiosis, and playful behavior make them a favorite among reef aquarists.
Why Choose a Yellow Watchman Goby?
✔ Bright yellow coloration with iridescent blue spots – Visually appealing.
✔ Pairs with pistol shrimp for a unique and interactive display.
✔ Hardy and adaptable, making them great for beginner and experienced aquarists.
✔ Can live long lives, up to 8 years in captivity.
✔ Reef-safe and beneficial – Helps aerate the sand bed.
⚠ Important Considerations Before Buying a Yellow Watchman Goby:
🚫 Can be territorial – Best kept singly or in a bonded pair.
🚫 Requires a fine sand substrate – Coarse gravel may cause injury.
🚫 Jumps when startled – A secure lid is recommended.