Saltwater Aquarium Blog

Ultimate care guide, facts, food, tips & more

The mandarin goby is arguably one of the most beautiful reef fish you will ever see. You may have also seen them listed as a mandarin: fish, dragonet, or even the psychedelic fish,

They are a small saltwater fish, generally reaching only about 3-4 inches in total length. Mandarin fish have a captivating swimming and hunting style to observe, which only adds to their charm. Their eyes seem to bug out of their heads and dart in all directions, looking for a tasty morsel of food, as they hover over the rocks and rubble.

Their primary means of propulsion and navigation is achieved by flapping their pectoral fins. When they do this rapidly, they look a bit like reef hummingbirds.

Surprisingly, they are also some of the least expensive fish you will encounter, in this hobby. 

This combination of amazingly good looks (I suffer from the same burden in life…NOT), interesting behavior and low cost of acquisition seem like the recipe for an ideal saltwater fish. 

However, these docile, psychedelic little gems are notoriously difficult for the beginner saltwater aquarium owner to care for—and often starve to death, under the watchful eye of their proud owners.

So, let’s dive a little deeper into the mandarin goby and find out what it takes to successfully care for them in your reef tank.

About the mandarin goby

The scientific names for the most commonly kept mandarin goby species in the reef aquarium hobby are:  Synchiropus splendidus and Synchiropus picturatus. What great choices in name, because they are each splendid, and picturesque—don’t you agree?

Their psychedelic coloration is what makes them unique and impossible to mistake for other species. Mandarin fish have scale-less bodies in blue, green, or orange-red, with a wavy pattern that creates a psychedelic impression. Even though many of us call them a (Mandarin) goby, they more specifically belong to the dragonet family.  I’m not exactly sure why, but when in doubt, it seems like people default to calling cool, small fish gobies (like with the engineer goby).

The good news is that, although they are small in size, this fish has a respectably long life by aquarium standards and an extremely long life, by goby standards. Their average lifespan is between 10- 15 years, and their small size makes them suitable for being kept in nano tanks (they only reach about 3 inches in length, some reaching up to 4 inches).

mandarinfish also known as mandarin goby

Mandarin Goby Ideal Habitat

In the wild, Mandarin Gobies can be found in the Coral Triangle, around Malaysia, Australia, Philippines or Indonesia, the Great Barrier Reef, and in the Indo-Pacific Ocean area. They live particularly in shallow lagoons and inshore reefs, especially around rubble beds or dead corals, which offer them protection and privacy.

Standard reef aquarium water parameters will certainly meet their needs, assuming you make your own saltwater with a reputable salt mix or buy from your local fish store and maintain your tank. The mandarin fish is best kept in a very mature tank with live rock, live sand, and a refugium. They prefer slower water flow and are picky eaters, so they don’t do well when mixed into the chaos of an SPS dominated tank or with gregarious and otherwise aggressive-feeding fishes.

The traditional advice is to keep them in a very mature reef tank because they will spend the majority of their days scouring the live rock and eating the tiny, natural fauna in your tank.

Your Mandarin dragonet will spend its days perched on and hovering just above the live rock, scanning the nooks and crannies for any morsel of food.

Feeding your mandarin goby

Notoriously fussy eaters, most mandarin gobies prefer live copepods and other tiny living crustaceans, over almost any other food item, which is why it is strongly recommended to keep this fish with a mature refugium, where natural stocks of copepods can be replenished. They may also accept live mysid shrimp, baby live brine shrimp, also called artemia, as well as other meaty foods, like black worms.

mandarinfish or mandarin goby

Behavior and Tank Mates for Synchiropus splendidus and Synchiropus picturatus

Mandarin Gobies are very peaceful fish that will never show aggressive behavior or get into trouble. Actually, it seems that other fish won’t even pay them great attention. On the other hand, they are very likely to act territorial towards their own species, so only consider keeping a single fish or a mated pair–males will attack other males.

Harems (one male with more females) have been successfully housed together, so this may also be an option, but is potentially best left to the advanced aquarist or would-be breeder.

Because they are shy fish, they like to have a lot of hiding places to feel secure. During the daytime, they like to stay hidden between rocks, but they may come out occasionally and hop through corals. It is best for them to be kept with other peaceful fish of the same size, as they cannot compete for food very well with larger ones.

They are not common prey among predator fish, although some scorpionfish are known to attack them from time to time, especially during mating times.

If they feel threatened, they may bury themselves in the sand, according to Scott W. Michael in his book: Marine Fishes.

You should also reconsider keeping these fishes if you also have an anemone. This slow-moving and docile fish has been reportedly eaten by anemones, even though they have that protective slime.

avoid buying mandarinfish as a starter saltwater aquarium fish

image by Luc Victour on Flickr

Picking the right one

Now that you know these are delicate fishes with very specific feeding requirements–it is important to consider some of the following characteristics below, to ensure you and your fish have the best chance for success.


Perhaps the most important consideration, when picking a mandarinfish for your reef tank–is to seek out captive-bred mandarins first. Aquaculture breakthrough for this species made a big splash several years back, and now numbers of these fish are provided into the hobby, sustainably raised through aquaculture.

These fishes are literally born and raised under similar conditions to what would be found in your tank–and they are also raised to accept commercial foods, which should also make caring for them a bit easier.

Well-fed and eating normally

Since we know that these species are finicky eaters, prone to starve to death in their home aquarium, it is important to look for signs of starvation when you pick the individual to travel home with. There are two signs to look for, in particular. The first, is whether the fish is actually eating in the local fish store.

Ask about whether the fish has been eating normally. Stop by the store during feeding time or ask to see the fish eat.

Also avoid any individuals (unless your plan is to rescue them) that look thin or malnourished. The classic sign of malnourishment is to look at the muscle on their dorsal side, just behind the skull. This should be one of the thickest parts of the body. If it is sunken in, that may be an indicator that fish has been starving.

Of course, the argument could be made that the starving fish needs your love and attention even more…just know that your money may become a charitable donation in that case, but your mission is commendable.

Varieties of mandarin goby

There are also a few different varieties of mandarin goby, commonly available in the hobby. A few of the most popular are blue, green and red mandarin gobies.

Synchiropus splendidus

The most popular, and commonly found mandarin dragonet is the Synchiropus splendidus species, which can be found in two different color forms–commonly called the blue mandarin goby or the red mandarin goby. These two fishes look substantially similar, with the same wavy coloration pattern, but with either blue or reddish/orange predominant tones, depending on whether you’re looking at the blue or red varietal.

mandarinfish also known as mandarin goby

Mandarin Fish - mating

Green mandarin goby

Synchiropus picturatus, also known as the green mandarin goby or the spotted dragonet, on the other hand, is an entirely different species of fish and has a distinct ring or spot patterns on a green background vs. the wavy designs found on their blue or red cousins.


Due to some pretty amazing advancements in the breeding of saltwater fishes, captive-bred dragonets have become available on the market. If you are looking to add this fish to your reef tank, I encourage you to see if your local fish store can get the captive-raised fish in for you.

There are al

Mandarin Fish Dragonet Interesting Facts

  • The Mandarin Goby gets its name from its bright coloration, which is similar to the robes of ancient Chinese officers, called mandarins
  • Although they are often called Mandarin Gobies, these fish are not indeed Gobies, but they rather belong to the Dragonet family
  • They are picky eaters, and you must pay great attention to what your specific fish would eat
  • They produce a noxious mucus to protect themselves from being eaten. Some believe their bright colors are a warning to would-be predators
  • Mandarin Gobies are safe to keep in reef tanks, as they won’t nip at corals or anemone, just make sure there is no more than a single male in the tank
  • They are picky eaters and don’t compete well for food, so pay great attention to their feeding time to make sure they stay healthy
  • They do display a limited amount of sexual dimorphism, which means that if you look carefully, you can tell males and females apart. Male mandarins have an elongated first dorsal spine when compared with females. This is generally not a bulletproof differentiator, because it is possible that females could be confused with less developed males, but it is at least one way for you to narrow down the lot if you are interested in trying to breed these fish at home
  • While they are generally inexpensive and widely available, they require a mature tank and are not good beginner fish

More Information about the Mandarin Fish

The mandarin fish dragonet is often one of the first saltwater fishes on a new aquarium owner’s wishlist, but since they require a mature reef tank with substantial natural foods to eat, they are not recommended for the beginner.

Check out these two articles to learn more about:

If you have a few minutes, please watch this video about the mandarin goby.

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