Minimum Tank Size 30 Gallons
Water Parameters 72-78 F, pH 8-8.4, Salinity 1.020-1.025
The Diamond Watchman Goby is a sand sifting blenny that combs the sand bed and rocks for food. They bring a lot of action, and some times chaos, to new and old tanks alike.
Tank Specific Need
These fish will typically clean out the sand bed, removing any micro fauna, copepods and beneficial bacteria that the tank may need. That being said, the Diamond Watchman Goby is best when paired with a strong refugium/sump. otherwise your tank will rapidly fall victim to ‘old tank syndrome’ where it can no longer filter out the nitrates that are being produced in the tank.
As the Diamond Watchman Goby is one of the most active sand sifters available you will need to ensure that any rock structures are secured in place. The constant digging performed by the goby can and will shift your rocks. For the least amount of change you can bury the rocks in the sand, having the base of the rock rest on the bottom of the tank.
Tank Mates to Avoid
While the Diamond Watchman Goby is peaceful and should not harm any other fish, they can become territorial when paired with similar sand sifters. If the other sand sifting fish has any level of aggression expect a fight. This often includes any other sand sifting gobies, but not jawfish.
Likewise you will not want to keep any fish that is reliant on copepods or food in the sand bed. This includes mandarins, scooter blennies, starfish and nassarius snails.
Finally, these fish make easy prey for highly aggressive fish. Avoid all eels, most hawkfish, with the flame hawk being a possible exception, large angle fish and triggers.
Diet & Feeding
The Diamond Watchman Goby feeds by sifting sand through his mouth, filtering out the small bits of food. In the wild this is no issue, as the sand beds are endless. In the home aquarium they will often run out of food. Once this happens they will quickly switch to prepared foods with little issue.
There will always be the case of the picky eater fish who will not eat. For the Diamond Watchman Goby, this can be solved using frozen, de-shelled table shrimp. Simply grate the shrimp from the goby and he will readily accept it. Should he miss the food it will end up in the sandbed for him to find anyways.
Remember that all fish need a balanced diet. Do not only use one type of flake or frozen food. Vary their diet and feed them twice a day at the minimum. These fish are meant to eat constantly through out the day by sifting the sand, so you may need to feed them a bit extra or bury some food in the sand every once and awhile.
When first adding your goby to the tank, always watch them eat their food. If the goby does not like the food he will pass it through his gills, basically spitting out the food. If this happens try a different food and see if they accept it. After a few foods you should find their preferred food. You can stick to this food as the acclimate to the tank and get settled in, however you will want to start varying their diet after a week or so.
Silly delivery aside they will happily eat many prepared foods once they are accustomed to the tank. Notice how the goby does not sift any of the food through his gills.
Breeding & Sexing
The Diamond Watchman Goby is a protogynous fish who can easily change gender when needed. However these fish are a bit finicky when it comes to the actual gender change. To make a pairing more likely purchase a second, much smaller goby than the original. Given the large size difference, dominance should easily be established, helping form a mated pair. If you have two similar sized gobies who have not paired, it is unlikely they will pair in the future.
Once the pair is made you simply need to keep the two fish happy and in a suitable environment. With a proper burrow, consistent feeding and a normal lighting schedule you can expect spawning to occur.
Diamond Watchman Gobies are not live spawners and will leave a clutch of eggs in the burrow. These can either be removed and incubated separately or left in the tank. Fry will easily hatch in the tank without any special attention, however they will be targets of other fish. For this reason I highly suggest investing in an isolation/incubation tank for any and all breeding purposes.