The Yellow Watchman Goby (Cryptocentrus cinctus) is a beloved reef fish, known not just for its quirky personality and perpetual pout, but for one of the most fascinating partnerships in the marine world. In the wild and in aquariums, this goby forms a symbiotic bond with pistol shrimp, acting as the vigilant lookout while the shrimp maintains a shared burrow. The shrimp keeps one antenna on the goby’s tail at all times, ready to retreat at the first tail twitch signaling danger. With eyes that move independently to scan for predators and a habit of hovering near its sandy home, the Watchman Goby is both adorable and functional.

While adults are typically bright yellow with turquoise markings, juvenile Yellow Watchman Gobies may appear steel blue. It is not easy to distinguish a male from a female but there is some speculation that the females are normally grayer in color. In this care guide, we’ll walk through everything you need to keep your Watchman Goby thriving, from tank setup and ideal water parameters to feeding tips and tank mate compatibility.

General Habitat & Tank Requirements:

  • Tank Size: A minimum of 20 gallons for a Watchman Goby.
  • Aquascape: Incorporate plenty of live rock to create hiding spots. Ensure the rockwork is stable, even if the sand shifts due to burrowing.
  • Substrate: Use sand as the substrate. Sand is easier for the Watchman Goby and its Pistol Shrimp partner to navigate through.

Water Conditions:

  • Temperature: 75°F to 80°F (23°C to 27°C).
  • pH: 7.7 to 8.5.
  • Specific Gravity (Salinity): 1.020 to 1.026.
  • Water Quality: Maintain ammonia and nitrite levels at 0 ppm, and nitrates below 20 ppm.
  • Filtration: Employ high-quality filtration, such as a protein skimmer, to ensure optimal water quality.

Diet and Feeding

Watchman Gobies are Carnivores, meaning they rely on meaty foods for their nutrition. This fish isn't typically a picky eater and will accept food in a variety of forms. 

  • Frozen or live foods like brine shrimp or mysis shrimp.
  • High-quality prepared foods such as pellets or flakes designed for small carnivorous fish.
  • Feed your Watchman Goby at least once a day.

Behavior and Compatibility

When it comes to tank mates, the Watchman Goby is peaceful and can coexist harmoniously with a variety of other marine species. It may show aggression towards its own species unless being kept as part of a mated pair.

Some Compatible Tank Mates

  • Fish: Clownfish, Tangs, Angelfish, Wrasses, Blennies, and other peaceful community fish.
  • Invertebrates: Pistol Shrimp, such as the Tiger Pistol Shrimp, are an ideal tank Mate, however, the Gobies won't bother most invertebrates, so Cleaner Shrimp, Hermit Crabs, Snails, Urchins, and more are all safe to keep.
  • Coral: The Watchman Goby is considered Reef Safe and can be kept with Soft, LPS, or SPS coral.

Behavioral Notes

  • Territoriality: The Watchman Goby may show aggression towards its own species unless being kept as part of a mated pair. This aggression towards its own species usually ramps up as the fish matures.

Health and Maintenance

Perform regular water changes of 10-25% every two to four weeks to maintain water quality. Regularly test water parameters and observe for signs of stress or illness, such as loss of color, appetite changes, or erratic swimming.

Common Health Issues

Gobies can be susceptible to common health issues in an aquarium environment such as:

  • Marine Ich: Identified by white spots on the body and rapid breathing.
  • Marine Velvet: Similar appearance to Ich but more severe, causing a dusty, velvet-like appearance on the skin.
  • Bacterial Infections: Open wounds from aggression or handling can become infected, leading to redness, swelling, or ulcerations.

Maintaining excellent water quality, providing the right nutrition, and giving the fish a stress-free environment can prevent most health issues.