Different names know Diamond Watchman Gobies. They’re known as the Orange Spotted Goby, Spotted Sleeper Goby, Maiden Goby, or the Diamond Goby.
These grow about 6 to 7 inches and are considered the ‘clean up’ crew because of their fondness for sifting through substrates looking for a bite to eat.
An average diamond watchman goby fish spends most of its time lurking at the bottom of the tank. The essential component of the marine tank is the substrate – experts recommend at least 4″ of soft sand.
Check out this care guide to learn more about this fascinating species.
Species Overview
Level of Care | Relatively easy |
Temperament | Generally peaceful |
Appearance | Orange and white |
Life Expectancy | Can live for 6 to 10 years |
Size | 6 to 7 inches in length |
Diet | Strictly carnivorous with a preference for live food |
Family | Gobiidae |
Tank Size | 50+ gallons |
Tank Environment | Marine tank having 4” of soft sand with corals, rocks, and caves |
Tank Mates | Live well with similarly sized docile fish |
Their Latin name is Valenciennea puellaris. They have well-developed immune systems, making them the last fish in any tank to get hit by diseases.
Diamond watchman gobies can be housed with tank mates that do not tend to eat invertebrates and other bottom-dwelling creatures.
They need a particular habitat type to thrive in an environment that meets their shelter, food, and breeding needs. Besides being fascinating to look at, Diamond Watchman Gobies have behavioral tendencies that are unique to them.
For instance, they will randomly rearrange objects in the tank, such as rocks and substrate, including other bottom-dwelling creatures. It can be a nuisance source for other animals, but they’ll get used to it pretty soon.
Appearance
Diamond Watchman Gobies grow to a size of around 7 inches in their natural habitat. In an aquarium environment, however, they reach a length of about 6 inches.
It is the ideal size for a community or reef tank. It has disproportionately large heads compared to its bodies equipped with strong jaws to displace large volumes of sand and gravel.
The rest of their fluorescent white body has distinct orange-yellow stripes that strongly contrast each other. It would be hard to miss them even when you have similarly colored marine fish swimming.
Their protruding, bulbous eyes make them look a bit funny, which becomes even more comical when they retreat into their sand substrate, only for one eye to peek out for a bit. These physical characteristics certainly add a unique dynamic character to any marine tank.
Behavior & Temperament
Diamond watchman gobies are very peaceful and get along well with other similarly sized docile fish with compatible temperaments.
There is one downside to keeping Diamond Watchman Gobies in a tank, though; these creatures have zero regards for their bottom-dwelling tank mates like clams, mushrooms, and corals.
They have a habit of taking mouthfuls of sand (and their mouth opens surprisingly wide) and then passing it through their gills. This sand is then dumped carelessly and indiscriminately everywhere, even onto their tank mates.
These also like to build mounds with sand throughout the substrate’s layers. The idea is to expel as many microorganisms out of the sand for the Diamond Watchman Goby to feed.
This behavior can be rather interesting to watch and could be addicting. Word of caution, though – you want to make sure the burrowing is done as a pleasure activity, not to seek refuge from predators.
It means removing the Diamond Goby predatory species like moray eels, groupers, lionfish, or large fish that could mistake them for prey and eat them.
Another thing to note about the Diamond Watchman Goby is that they are fond of jumping – and they’ll do this a lot. As long as they can fit through a hole, these tiny ‘escape artists’ will squish themselves through small crevices to escape – and probably die if you don’t intervene soon enough. Make sure the tank is safe and secure with a tight lid that cannot be displaced easily.
Hiding Behavior
It is not unusual for them to hide for prolonged periods. They do this out of habit and should not be disturbed when doing so. However, if they’re doing this because of nearby predators, it’s time for you to intervene. Your goby should emerge from hiding in just a few days when it’s safe enough.
Reef Safe
Most diamond watchman gobies are safe for a reef tank and will leave corals and invertebrates alone. However, it is worth noting that some species may get a little territorial and consume copepods if there isn’t enough space or if it’s not getting enough nutrition.
Tank Mates
As mentioned earlier, you must avoid predatory animals or other large fish that could mistake your goby for prey. However, you can keep them in the same tank with other peaceful marine fish, including clownfish and damsels.
Below is the complete list that is fully compatible with Diamond Watchman Gobies.
- Clownfish
- Damsels
- Shrimps
- Filefish
- Dwarf Angelfish
- Pink Fairy Wrasse
- Foxface Rabbitfish
- Cleaner Wrasse
It is worth noting that Diamond Watchman Goby fish will become territorial and aggressive when placed near their kind. It is recommended to keep just one in a tank or a Diamond Watchman Goby pair. Otherwise, all the in-fighting could result in the death of one of the marine fish.
Food & Diet
Diamond Watchman food is exclusively carnivorous, involving live foods such as brine shrimp, krill, copepods, and Mysis. Their favorite foods include tiny zooplankton as well as accumulated detritus from tank habitats.
They also prefer to eat mini sinking pellets and flaked food. That being said, they will gladly gobble up frozen food too, make sure to defrost it in tank water before placing it on the substrate of the tank using a turkey baster or a feeding tube. Please make sure any other fish don’t eat the food on its way down.
As a general rule of thumb, you should introduce foods small enough for Diamond Watchman Gobies to filter with their mouth and eat.
It is recommended to feed the Diamond Watchman Goby at least 2 to 3 times every day. Make sure the food portions are small and should be eaten within2 to 3 minutes.
Depending on the fish in the tank, Diamond Watchman Gobies can often miss out on their food because the other faster species will gobble up all the food before it even reaches your goby. It may be essential to supervise the feeding patterns of your goby and other tank mates.
Tank Setup

Diamond Watchman Gobies should be contained in a tank that is at least 50+ gallons with more width than depth. It provides them with the ideal environment to create and mark their territory and a deep, comfortable burrow to live.
Water Conditions
Below are the perfect water conditions you should strive to achieve:
- Temperature: 73 °F to 78 °F
- pH Value: 8.2 to 8.4
- Specific Gravity: 1.021 to 1.025
- Minimum 4 inches of soft sandy substrate
Diamond Watchman Gobies are known to be exceptionally active. They will need a tank that has a strong sump or refugium to ensure they get ideal water conditions and provides them with plenty of copepods to eat.
Rocks & Substrate
The key to adopting a Goby is to provide it with a suitable sandy substrate. It should be several inches deep for it to burrow inside safely. Many experts argue that Diamond Watchman Gobies need at least 3 to 4 inches of soft sand in the aquarium to mimic their natural habitat and feed on tiny microorganisms that hide in the sand.
Diamond Watchman Gobies will displace any rocks and plants that get in their way and are not firmly secured in place. In many cases, Gobies may even decide to rearrange the tank and shift the interior décor around. It is dangerous to both the gobies and other fish in the tank that share the same space.
To secure the rock in its place, you can push it deep into the sand with its base at the bottom of the tank. It makes them stable enough to keep your Diamond Watchman Gobies safe and secure.
Filtration
This marine fish deserves the best possible water conditions, which require an above-average filter. Something like the Penn Plax Cascade Canister Aquarium Filter will do a phenomenal job keeping the water in excellent condition.
Because they’re so active in their tank, it becomes necessary to change 25% of the water every two weeks partially.
Plants
To make your Diamond Watchman Goby feel at home, it may be essential to add marine plants to the tank. These plants will allow macroalgae organisms to thrive,
which could be used as a food source for your bottom-dwelling invertebrates. Besides, if you’re going for a reef tank, it wouldn’t be complete without plant addition.
Here are a few great ideas for an aquarium:
Tufted Algae
These plants are ideal for reef tanks because they easily hold on to most substrates and rocks. In the wild, tufted algae can be found along the coastal reef habitats growing in segments and tufts.
The best part about them is that they don’t need excessive lighting to survive. Many aquarists use these plants to test the water conditions. If they’re doing okay, the chances are that the rest of your fish are also doing okay.
Shaving Brush
They resemble a shaving brush and look ready for some shaving cream. These algae are very hardy and can thrive in a variety of saltwater tanks.
Their roots can secure themselves to just about anything, including sandy substrates. They do not have many predators, except for sea urchins.
Cactus Algae
This plant features a tough tissue that uses calcium carbonate to survive. Make sure to keep an eye out for this mineral if you want to care for this plant. It can grow out of control and compete with calcium that your fish may depend on. A few tangs will keep their excessive growth under check.
Green Feather Algae
These plants are sometimes referred to as Mexican water plants because they are abundantly found along the Gulf of Mexico. They resemble ferns and are exceptionally durable, with the ability to survive a range of water conditions.
These plants provide a good source of nutrients to saltwater fish, but most species stay out of their way.
Dragon’s Tongue Algae
The Dragon’s Tongue Algae is the easiest way to spruce up your saltwater tank because of the distinct deep, red color. They grow fast and are suitable for most marine tanks. Just make sure to watch out for herbivorous species that may be too attracted to this gorgeous plant.
Green Finger Plant
The Green Finger Plant is aptly named for small finger-like growths that resemble little fingers and even antlers on a deer. Most saltwater fish will stay away from the green macroalgae.
They’re ideal for saltwater tanks because they provide the necessary filtration and oxygenation to keep your tank looking beautiful and fresh.
Breeding Guidelines

It can be challenging, not impossible, to breed Diamond Watchman Gobies in an aquarium setting. The tricky part is getting to pair them correctly, and that is easier said than done.
It is because males and females have no easily distinguishable physical characteristics and can change their gender on a whim!
This ability conveniently allows the fish to sustain their numbers in a sparsely populated area in the wild. It is recommended to ask an expert in your marine store to determine the sex of the Diamond Watchman Goby before you decide to buy it.
When they do decide to breed, the pair will place their fertilized eggs over the sand burrows. Male diamond watchman gobies will guard their eggs until they hatch after just a few days.
You’ll have to be on ‘standby’ mode because once the fry emerges, you’ll have to nourish it with plenty of food involving live plankton.
It is the hard part because plankton is not easy to come by. You may have to order a supply of live plankton from a specialist supply store. A diet of plankton will enable the fry to survive and grow.
However, if you want to maximize their growth chances, you’ll need to remove them from the main tank and replace them in a special nursery tank to prevent them from being eaten by predators.
Fry will attract attention from nearby fish and get eaten. It makes it essential to separate them as soon as possible.
Diamond Goby Common Diseases
While it’s true that Diamond Watchman Gobies are a hardy species with well-equipped immune systems to fight infections and bacteria – it’s better to prevent something wrong before it happens.
They can just as quickly get Ich, a fish disease caused by bacteria that primarily attacks saltwater fish. This disease causes the affected fish to develop abnormal white spots on their gills.
Symptoms include unusual hiding behaviors, scratching, and abnormal swimming patterns. If left untreated, the goby may contract secondary bacterial infections and die as a result.
The main reason why they get infected at all is high levels of stress. Another reason could be that your tank lacks the appropriate environmental conditions needed to house a Diamond Watchman Goby.
Provide your Diamond Watchman Goby fish with a clean, well-filter aquarium and compatible tank mates. Make sure the tank has stable water chemistry that doesn’t fluctuate from one extreme to another.
The less stress your fish has, the stronger the immune system will be – and the longer it will live as a result.
Where to Buy?
You can buy Diamond Watchman Gobies from most saltwater aquarium specialist stores, online forums, and online stores. Before purchasing the Diamond Watchman Goby for sale, you should inspect them for signs of health defects.
If you plan on breeding them, ask an expert to verify their gender to help you pair them with another goby. In some cases, the females may be larger – but this is not always the case.
The average price for a Diamond Watchman Goby is around $30 or more, depending on availability and where you live.
Wrapping Up
If you are looking for a new addition to your saltwater tank and want something a bit out of the ordinary, consider adopting a Diamond Watchman Goby.
They don’t have much in the way of requirements, have unusual behavioral patterns that are endlessly entertaining, and will make your marine tank look downright stunning.
They get along well with most saltwater tank mates, except their kind and other burrowing gobies. The care guide is simple for most beginners to follow.