Yellow Watchman Goby & Pistol Shrimp Koh Tao


Learn about Watchman Goby & Pistol Shrimp on Koh Tao

Yellow Watchman Goby & the Pistol Shrimp are possibly one of the most dazzling duets on Koh Tao and over the years they have formed a formidable relationship for survival and reproduction.

How much do you know about their awesome partnership?

Must-See In Koh Tao: The Incredible Yellow Watchman Goby & Pistol Shrimp |

Where to find the Yellow Watchman Goby & Pistol Shrimp on Koh Tao

If you swim higher than a few metres above the sandy bottom of any dive site on Koh Tao, you will be hard pressed to see these guys and most scuba divers swim over the top of them without even noticing.

The Watchman Goby and Pistol Shrimp can be seen at nearly every single dive site on Koh Tao with places like Hin Wong Bay, Aow Leuk Bay and Shark Bay offering perfect places for snorkelers.

How to identify Yellow Watchman Goby and Pistol Shrimp

Yellow Watchman Gobies are mostly a yellow-orange colour and have bright blue spots on their head and fins.

They often have an amusing frown on their face as they poke their head out from rocks or their sand burrow and grow no more than a few centimetres in length.

Pistol Shrimps can roughly grow to the same size as the Yellow Watchman Goby and they have a very unique appearance.

Symbiotic Relationship

They can have many colour variations at different locations around the world and the easiest way to identify them is by a disproportionately large claw on one side of the body.

Amazingly, if the claw is broken off, it can grow back with the opposite side growing into the new larger claw.

The most common way of identifying these two is by the interesting relationship they form, commonly referred to as a symbiotic relationship.

They can be seen living together in a hole in the sand, known as a burrow with the Watchman Goby poking its head out, hence the name.

Yellow Watchman Goby & Pistol Shrimp
Yellow Watchman Goby & Pistol Shrimp

Watchman Goby and Pistol Shrimp Characteristics & Behaviour

Living together in a confined space may seem a bit strange considering they have the entire Ocean floor to choose from however, by forming a symbiotic relationship they have managed to become the perfect housemates.

Yellow Watchman Goby have incredibly good eye sight, which is great news for the Pistol Shrimp as it is almost blind.

Yellow Watchman Goby spend their time outside of the burrow watching out for any nearby predators.

Watchman Goby & Shrimp Koh Tao

If any threat is perceived, the Watchman Goby bangs its tail on the bottom of the sand, which tells the Pistol Shrimp to retreat and they both quickly reverse back into the safety of their home.

The job of the Pistol Shrimp is to build their burrow and keep it tidy and if you spend any time watching these two, it is safe to say the Pistol Shrimp is obsessive about cleanliness.

If both of them venture out of the burrow they will stay in very close contact and the Pistol Shrimp will often stay behind the Yellow Watchman Goby and maintain contact by the use of its antennae.

Goby & Shrimp - Symbiosis
Goby & Shrimp – Symbiosis

Interesting Facts about Watchman Goby & Pistol Shrimp

Pistol Shrimps have an amazing trick up their salty sleeve and when hunting they can use their larger claw as a snapper by opening it up and quickly closing it together.

This snapping movement happens at the blink of an eye and causes a powerful low-pressure cavitation bubble.

The cavitation bubble effect has been recorded at 62 mph and heats up to around 4700 °C, which is almost as hot as the sun.

The final blow is delivered when the bubble bursts with a loud sound that stuns prey and this entire process happens within 300 microseconds and the sound can reach up to 218 decibels.

Use a Large Claw as a Snapper

To put that into perspective, the snapping effect is louder than the sound of a gunshot, hence the name the Pistol Shrimp.

When Pistol Shrimps are in a colony and all snapping together, they can interfere with underwater communication and sonar.

Yellow Watchman Goby have the ability to change their gender either way within a matter of days.

This has helped Goby populations stay strong and males are thought to use this ability when in an environment surrounded by more dominant Gobies of the same gender.

Watchman Goby & Shrimp Mutualism
Watchman Goby & Shrimp Mutualism