The Yellow Watchman Goby is a stocky, bright-yellow (sometimes grey) goby known for its symbiotic partnership with pistol shrimp.
The near-blind shrimp digs and maintains a burrow while the sharp-eyed goby stands guard, retreating into the shared den at any danger.
It is hardy, peaceful, and reef-safe.
Even without a shrimp it makes a charming bottom-dweller, perched on the sand watching the tank with its large eyes.
Its burrowing and sand-sifting behaviour helps keep the substrate turned over and aerated.
Housing
Provide a cycled 110L (30 gal) tank with a deeper sand bed (5 cm+) for burrowing and live rock placed on the glass so digging cannot collapse it.
Keep salinity 1.024-1.026, temperature 23-27°C (74-80°F), pH 8.1-8.4, and nitrate low.
A secure lid is important because, like other gobies, they jump.
Pair it with a single Tiger or Randall's pistol shrimp for the classic partnership.
Stable water and a soft sand bed it can excavate keep this goby content and natural in behaviour.
Diet
The Yellow Watchman is a carnivore.
Offer frozen mysis and brine shrimp, finely chopped seafood, and sinking marine pellets, fed once or twice daily.
It will also sift the sand for tiny morsels and microfauna.
Most individuals feed readily once settled, though shy ones eat more confidently with their pistol-shrimp partner present.
Ensure food reaches the bottom, as this goby rarely chases food high in the water column and can be outcompeted by faster fish.
Health
Watchman gobies are hardy and disease-resistant in stable water.
The main risks are jumping from an open tank and stress from aggressive tankmates or unstable parameters, which can lead to ich or bacterial infection.
Quarantine new fish, keep nitrate low, and provide secure burrows.
Watch that it is getting enough food, since a thin, hollow-bellied goby signals it is being outcompeted.
A calm, sand-bedded tank keeps it healthy for years.
Temperament
Peaceful and reef-safe, the Yellow Watchman spends its time guarding its burrow and watching the tank.
It is harmless to corals and most tankmates but may squabble with another bottom-dwelling goby over territory.
Keep one per tank unless adding a bonded pair, and avoid housing it with larger predators or very aggressive fish.
With its pistol-shrimp partner it shows interesting cooperative behaviour that makes it a standout reef resident.
A good fit for
Beginners wanting interesting behaviour
Sand-bedded reef tanks
Keepers wanting the pistol-shrimp pairing
Peaceful community stocking
Common mistakes to avoid
No lid - they jump from the tank
Shallow sand prevents natural burrowing
Rock stacked on sand can collapse on burrows
Aggressive tankmates outcompete it for food
Is your enclosure big enough?
Minimum volume110 litres (29 US gallons)
CompanyFine alone or with company. Singly or pair; pairs with a pistol shrimp
In a reef, stability matters more than any single target number. A parameter moving fast does more damage than a parameter sitting slightly off.
Go now
Any detectable ammonia or nitriteWater change now with matched, mixed and aerated saltwater. Stop feeding. Directly toxic, and a marine system has less margin than a freshwater one.
Now
Temperature or salinity has moved sharplyCorrect slowly, over hours, not minutes. Check the heater and the top-off. The speed of the change does the damage. Correcting fast repeats the injury in the other direction.
Now
Rapid gilling, or a fish hanging in the flow breathing hardIncrease aeration and check temperature and salinity. Warm water holds less oxygen, and a heater failure shows up here first.
Now
Today
White spots, or a fine dusting like icing sugarIdentify which parasite before treating. Most reef tanks cannot be treated in place. The two common parasites look similar and need different handling; velvet can kill a tank in days.
Today
Corals closed for more than a day, or receding tissueTest alkalinity first, and compare it against the last reading rather than a target. Unstable alkalinity is the most commonly cited coral killer, and a swing shows up in the trend, never in a single point.
Today
A new fish added without quarantine now looks unwellRemove it to a separate system today if you can. Nearly every wipeout in a reef tank traces back to a skipped quarantine.
Today
Quarantine every new animal, including corals and inverts. It is the single practice that separates a reef that lasts from a reef that restarts.
This is general guidance for a healthy adult, not a diagnosis. An exotics vet who knows your animal always overrides it — and the time to find one is before you need one.
What it really costs
Setup, monthly, first year and across a whole life, itemised and with the electricity worked out from the actual wattage. Published figures for the same animal disagree by a factor of four, so the calculator shows ranges rather than picking one.
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