The bright yellow watchman goby, also known as the yellow prawn goby, is a fascinating saltwater aquarium fish. It’s suitable for beginning marine aquarists, does well in smaller aquariums and its bright coloration makes it a cheerful addition to your tank.
Keep reading for everything you need to know about yellow watchman goby care and keeping these gobies in your home aquarium!
| Name (Common, Scientific) | Yellow watchman goby, yellow prawn goby, spotted watchman goby, sulphur goby, Cryptocentrus cinctus |
| Minimum tank size | 20 gallons |
| Minimum group size | 1 |
| Temperature | 72–82 °F |
| Salinity | 1.020–1.025 |
| pH | 8.0–8.4 |
| Difficulty level | Easy |
Yellow watchman goby description & natural habitat
Description
The yellow watchman goby is a bottom-dwelling member of the family Gobiidae. Contrary to what its name suggests, it’s not always yellow in color, but can also be brown, grayish, olive, or cream. One thing all specimens do have in common are the neon blue flecks across the fronts of their bodies and their dorsal fins.
This goby can grow to up to around 4” in length and sports large eyes and a comically large, frog-like mouth.
Natural habitat
Naturally found in the eastern Indian Ocean and Western Pacific, from India to New Caledonia (past Australia), the yellow watchman goby calls the reef home. It’s a well-known inhabitant of the iconic Great Barrier Reef.
This goby is found from the shallows to depths of up to 82 ft, where it inhabits burrows in the sandy substrates of protected lagoons and seagrass beds.
Did you know? Although large amounts of yellow watchman gobies are taken from the wild for the aquarium hobby each year, they’re considered a species of Least Concern by the IUCN Red List. Still, we hope that one day soon, all of those available in local aquarium stores will be captive bred.
Yellow watchman goby aquarium
Goby ♥ Shrimp
Part of what makes the yellow watchman goby such a fascinating aquarium fish is the symbiotic relationship it forms with alpheid shrimp species. In the aquarium world, these are better known as pistol shrimp or snapping shrimp.
Although pistol shrimp carry a formidable punch, their eyesight is extremely limited. That’s where the yellow watchman goby comes in, and where it gets its common name from! This highly vigilant fish keeps an eye out for the both of them, thereby ensuring the pistol shrimp’s safety. If danger occurs, the alarm is communicated to the shrimp by means of touch.
In the aquarium, your yellow watchman goby doesn’t need to be accompanied by a pistol shrimp. This being said, they often end up looking a little forlorn without their natural partner, spending most of their time hiding in the safety of their burrows. They’re much bolder when they have their bodyguards around, plus all those little goby-shrimp interactions are fascinating to watch.
Note: Pistol shrimp can’t break aquarium glass like some sources suggest, though larger specimens can pose a threat to ornamental shrimp.
Aquarium set-up
Because yellow watchman gobies are small and don’t tend to move very far from the safety of their burrows, they don’t need a large tank to thrive. A 20 gallon set-up should probably be enough for a single watchman; if you’d like to keep a mated pair, you could consider a 30-gallon tank.
Because yellow watchmen and their shrimp buddies are burrowing bottom dwellers, your aquarium will need a sandy substrate. A mix of fine sand and coarser coral rubble around 4″ deep allows the shrimp to build the pair a home with good structural integrity. Do consider gluing the hardscape to the bottom of the tank so it can’t shift from all the tunneling!
Make sure there’s a mix of hiding places as well as more open spots available throughout the tank. Your watchman will appreciate being able to wait out in the open for food, but wants to be able to dart into its burrow at the slightest sign of danger.
Note: Your aquarium should have a tight-fitting lit. Gobies are prone to jumping when startled — and they spook pretty easily.
Yellow watchman goby compatibility
One of the reasons reef keepers love yellow watchman gobies so much is that they’re peaceful and will get along swimmingly with other inoffensive tankmates. Small numbers like the species on our list of beginner reef fish make excellent choices, as do some larger herbivores like foxface rabbitfish and yellow tangs. Just keep the shrimp in mind — something like a Thalassoma wrasse probably won’t bother your watchman, but it might view a small pistol shrimp as dinner.
Also remember that although it won’t mind anyone swimming above it, a watchman goby can become fiercely territorial when other gobies are involved. Unless you have a lot of space to offer everyone, it’s best to stick to a single watchman or a mated pair to prevent brawls.
The yellow watchman goby is considered reef safe, making it a great choice if you also want to grow corals. The worst it’ll do to your corals is sit on them occasionally. Pistol shrimp can drag small frags sitting on the substrate into their burrows to improve the structural integrity, so consider growing those out until they’re too big to serve as building materials.
Yellow watchman goby diet
In the wild, the yellow watchman goby sifts the sand in search of algae and small meaty bits (this is called a zoobenthivore). This species is not picky when it comes to food, which is one of the reasons it’s such a great option for beginning aquarists. Marine fish flakes or sinking pellets should happily be accepted.
Aside from commercial aquarium fish foods, you can also offer (thawed) frozen foods like mysis and brine shrimp. Just make sure your yellow watchman goby actually gets its fair share: because it’s a bottom feeder and a bit timid, it might be outcompeted by more boisterous tankmates.
Breeding yellow watchman goby
Unlike many other marine fish, the yellow watchman goby breeds in the aquarium. These gobies are produced on a commercial scale by ORA Farms, but it should also be possible to get yours to reproduce at home. A happy and healthy pair of yellow watchman gobies will usually spawn without any effort on your part. If you have some experience, you may be able to raise the fry.
The pairing up of yellow watchman gobies isn’t too challenging, as they can change their sex. Placing two individuals together will often eventually result in a couple, with the female (or the fish that changed to female) taking on a grayish hue. You can also try introducing a yellow-colored fish to a grey one.
To breed your gobies, it helps to move the pair into a dedicated breeding set-up (20 gallons, for example). Make sure there are plenty of caves and tubes available to help them feel safe and provide a place to spawn. Using loose décor pieces also allows you to easily pull the nest later in order to move it into a separate hatching tank (something like a 10-gallon, maybe not filled to the top at first).
As mentioned in Amy Drehmel’s brilliant yellow watchman breeding report, the eggs hatch after just 4 days. This immediately presents the biggest challenge in breeding these fish: their babies are so tiny! Much smaller than baby clownfish, for example. This means they need to be fed very, very tiny foods as well. Drehmel recommends s-rotifers, which only grow to 150 microns (that’s zero point fifteen millimeters).
Once the fry have grown, you can move to larger rotifers and then other small foods.
Conclusion
Whether small or large, a marine aquarium featuring a yellow watchman goby and its trusted pistol shrimp sidekick is a fascinating addition to your home or office. If you’re dreaming of your own reef, contact us so we can design, build and maintain it for you.
