diamond goby live rock

Diamond Goby Care

The Diamond Goby is a peaceful reef fish that will liven up your tank with a subtle burst of color (spots) and personality. They are a reasonably hardy species of fish that should be easy for beginners or advanced hobbyists to care for--and watching them dig through and sift the sand like a prospector is loads of fun to watch. This article will share some more interesting facts about the Diamond Watchman Goby and how to care for it in a saltwater aquarium.

Table of contents

This article is broken down into the following subtopics around Diamond goby care. You can use the links below to jump down to a specific section.

diamond goby

The Diamond Goby is a great sand-sifting community fish with a cool personality

A few quick facts about the Diamond Goby:

  • Scientific Name: Valenciennea Puellaris
  • Common Names: Diamond Goby, Diamond Watchman Goby, Orange Spotted Goby, Diamond Sleeper goby (these names will be used interchangeably in this article
  • Max Size: 6-Inches
  • Minimum Tank Size: 20-gallons (long)
  • Aggression Level: Peaceful
  • Color: White, Orange, Yellow
  • Care Level: Easy and suitable for beginners
  • Most Active: Day
  • Lifespan: 5 to 8 years in captivity could be expected (please leave a comment at the bottom of this article to share your own experiences)
  • Diet: Meaty foods (carnivorous)
  • Price: ~$30-$45 range
diamond goby in quarantine

This diamond watchman goby is in quarantine before being approved to go into my display tank

Natural habitat

Like many of the other saltwater fish available in the reef aquarium trade, the Diamond Watchman Goby originates from the reefs in the Indian and Pacific Oceans and can be commonly found around the Great Barrier Reef and Red Sea areas. They tend to prefer lagoon habitats or along the outer reef, in the wild.

The Diamond Watchman Goby is a sand sifter and spends a lot of their time gulping in mouthfuls of sand and raking through it for tiny morsels of food. They suck the sand in through their mouths and then expel it out their gills. It’s fun to watch.

Orange spotted goby swimming in a reef tank with Favia species in background

Note how the Orange spotted goby gets its name

Aquarium care guide

The Diamond Goby is a medium-sized fish. 6-inches is the fully grown length, but they are a relatively compact, torpedo-shaped 6-inches. They will dig out a burrow under the live rock and will stay on or close to the sand, sucking in and sifting the occasional mouthful of sand. 

Minimum tank size for the Diamond Watchman Goby

At about 6-inches in length, when fully grown, they are a medium-to-large sized saltwater fish, but since they are relatively substrate attached, they can be kept in a 20-gallon long-style tank, which is 30-inches x 12-inches (76 centimeters x 30.5 centimeters. If you have more sand-dwellers than that in your tank (Engineer gobies, jawfish, etc.) you probably want a minimum tank size that is twice that size and should probably use caution because you may end up with some aggression and fighting.

Substrate and structure suitable for the Orange Spotted Goby

Since they are burrow-digging sand sifters by nature, perhaps the most important element to the healthy, natural care of the Diamond Goby is to have a deep sand bed (DSB) suitable for being sifted through. It is possible to keep them in a bare-bottomed tank, but it would be unnatural for you and the fish…so…why bother.

Diamond goby on a large rubble substrate with red slime algae

Note that the large rubble substrate in this picture is not ideal for the diamond goby, who will sift through the sand, if given the chance

It’s not very likely that you would have a saltwater aquarium without live rock or some other structure, but it is worth mentioning the importance of the structure for the natural behavior of the fish. If you can meet both of these conditions, you will likely be rewarded with a healthy, peaceful fish that will dig under the rock and sift through the sand, finding tiny morsels to snack on, while keeping things tidy and the top layers oxygenated.

Feeding the Diamond Goby

Watching the Diamond Goby forage in the sand and sift it through its mouth and gills is interesting and fun to watch. They are carnivorous fish that usually searches the sand bed for their meals. But do not rely on them to meet their own nutritional requirements in your tank without proper feeding. They are carnivorous and should accept live or frozen brine shrimp, mysis shrimp, live blackworms, and copepods, and other prepared marine foods, in addition to whatever meaty morsels they find while foraging in your sand bed.

It is also recommended that you take a moment to make sure they’re getting enough food to eat. Given the fact that they live on the bottom and that they are very peaceful, it is possible that the greedier fish in your tank swoop up all the food before they get their share. If that’s the case, you may want to do some directly targeted feeding, as well. Starvation is sometimes reported in this species.

They are also reported to eat some smaller bristleworms.

Compatibility

Orange spotted gobies are reef safe and will leave your corals and other invertebrates alone. They are also peaceful community fish that will get along with the other non-aggressive saltwater fish in your aquarium. There are two conditions under which they are known to predictably display aggression:

  1. When kept in the same aquarium with other Diamond gobies (that are not an established or mated pair), or sleeper gobies
  2. Defending their territory against encroachers.

Species to avoid keeping with the Diamond Watchman Goby

There is likely no surprise to this advice, but don’t keep the Orange spotted goby with any aggressive or predatory fish that would consider them dinner, or even a light snack. A few easy examples of fish to avoid keeping concurrently would be Lionfishes, Groupers, Picasso Triggerfishes.

It is advised not to keep them with semi-aggressive species like the more pugnacious dottybacks, damselfishes, etc.,

Good pairings

Due to the peaceful disposition of the Diamond Sleeper Goby, there is actually a lot of suitable pairing, but here are a few suggestions to get you started: Firefish gobies, Lawnmower blennies, Marine Betta, Pajama cardinalfish, Neon goby…and on, and on.

That is not an exhaustive list, just representative of a few good choices.

Breeding and reproduction of the Diamond Watchman Goby

While you should expect to see aggression if you mix two or more non-bonded Diamond gobies in the same tank, it is possible to establish pairs or to purchase previously bonded pairs. They share a burrow and will lay their eggs inside the burrow.

diamond goby pair in reef tank behind zoanthids

The male will guard the eggs for ~3-4 days until the larvae emerge after lights-out.

Diamond goby larvae are phototropic and can be attracted to the surface with a flashlight or captured with a larval snagger. The fry are fragile and difficult to rear, even by saltwater fish standards.

Check out this site for more information about breeding them. 

Diamond Watchman Goby hiding

The Diamond goby is a digger and likes to spend time in their burrow. At night, or when spawning (if you have a pair) they will even cover up the entrance. Don’t panic if you don’t see them for a few days; this is normal behavior for this species.

A bit about their common names

It is interesting to see that this awesome fish has several very different common names--but why do they have ‘Watchman’ and ‘Sleeper’ middle names? I don’t have great answers to these questions, but I did look them up.

Why are they named “sleeper” gobies?

There isn’t a lot of great mystery or intrigue here, but according to Encyclopedia Britannica, they’re called sleepers simply because they peacefully exist on the sandy floor.

Why are they called “watchman” gobies

The tag Watchman is a little more straightforward and is thought to be associated with the fact that some goby species have a symbiotic relationship with certain shrimp, like the Pistol shrimp, that have poor eyesight. The gobies literally do keep watch. It is a bit of a misnomer in this case since this sand-sifting species isn’t generally the type to pair up with a shrimp.

Here’s my reaction to this:

Orange spotted goby cost and for sale

The Orange spotted goby is generally in the $30-$45 price range, from what I’ve seen. They are not one of the most popularly imported saltwater fish species, so you may not see them routinely in your local fish store. They are commonly purchased enough to be relatively available on the major online retailers.

Conclusions

The Diamond goby is a great saltwater fish for any community reef aquarium with a deep sand bed (that doesn’t already have a burrowing resident). They are energetic, amusing to watch, and full of personality. Peaceful in nature, and reef safe, they are compatible with many of the most popular fish, corals, and invertebrates. They can get to be a decent size, when fully-grown, but don’t require a lot of swimming room. Rather, the most important care aspect is ensuring enough sandy real estate for them to call home.

What to read next

If you are looking for saltwater fish with big personalities and behaviors that are fun to watch, check out these other great species:

If you’re just starting out, here is a great resource to plan out the set up of your saltwater aquarium

For more information

If you want to learn more about the Orange spotted goby, check out this video:

Diamond Watchman Goby Sifting Sand

References

Michael, Scott W. Marine Fishes: 500+ Essential-to-Know Aquarium Species. TFH Publications. Neptune City, NJ: 2001.

Diamond watchman goby care guide

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Comments

  1. Hi, you forgot to mention they can sift out the sand, after swimming upwards, all over corals etc.
    But they are comical.
    Cheers,
    Tony.

  2. Hi this Austin again. I would like to add this fish to my 75 gallon. My worry is that it might starve. I’ve watched some videos that they may starve if there isn’t microfauna in the sandbed and that the sandbed should be mature. I do not want to do this to the poor little fish. I will wait if I have to. I know you said that in the article to feed them mysis, etc and to not rely on them to find food in the solelky in the sandbed. I don’t understand why they would starve if they are eating what you are feeding them. I’ve heard of people putting food in the sandbed. People have also said to get one from your LFS that is eating mysis and pellets.

    P.S- My tank is cycled and I have a pair of Ocellaris Clownfish. I also decided not to get the cleaner shrimp. I decided to get the Flame Hawkfish.

    1. Author

      Hi Austin,

      Thanks again for the comment. These are great-looking fish. I do think you’re on to something. If they are eating what you feed them, they will not starve. My guess is that those people who had issues with starving fish were unable to get it to take the regular aquarium foods. Unfortunately, that happens some of the time, more common with wild-caught fish like this.

      Sending you good luck vibes if you choose to get one. Double checking that it is eating before you bring it home is a good idea.

      Regards,
      al

  3. Hi this Austin again, I decided I am going to get one, but I am going to wait for about four more months to get to let my sand bed mature. I think I might have figured out the problem on them starving. I read a reef2reef forum that asked why their diamond goby was skinny even though they fed. Several of the people said that if it is eating and he is still skinny that he might have an internal parasite. Then I watched a BRS video on gobies and nutrition and that internal parasites can actually be common in gobies.

    1. Author

      Hi Austin, thanks for coming back and sharing what you found after your research. You bring up a factor I hadn’t considered in my earlier reply. I was focused on nutritional contribution of the inverts in the substrate and the feeding. But you bring up a good point about parasites contributing to weight-loss even when the fish is eating well. It is really important to get any new fish acclimated to the commercial foods you’re feeding to help them keep their strength up. Thanks again for your contributions!

      Regards,
      Al

  4. Hi, this is Austin again. I think another reason on people not getting their gobies to eat is internal parasites. I read a reef2reef forum asking why their diamond goby was skinny even though they were feeding it. Several of the people answered back that he could have internal parasites because he shouldn’t be skinny if was eating. Then I watched a BRS video that said that internal parasites can be common in gobies.

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