An explosion of color, the Mandarinfish or Psychedelic Fish, elicits more “wows” and “ahs” than most other saltwater fish; often being the fish that brings new aquarists to the hobby.

The elongated body of this beauty consists of orange to dark reddish orange, covered with greenish turquoise squiggles, lines and bars and orange to red eyes.  The fins have more of the orangish red to red coloring with electric blue accents although the dorsal fin has more of the body’s coloring.  Their head is green with electric blue lines that run between the eyes, a pale chin and a very small protruding mouth.  Males are larger and have a longer front dorsal spine.  For defense they use their coloring, sharp spines on their cheeks and noxious slime coating.  The males can grow to 3.1” (8 cm), which are a little larger than their polka dotted counterparts and they live 10 to 15 years.

Mandarinfish are often referred to as the Mandarin Goby, however, like the Engineer Goby, neither one is actually a goby!  These Dragonets have a noxious mucous layer and are scaleless, so do not treat them with any copper products.  These little guys will help control brown flatworms that plague some aquariums.  At night, they turn pale and sleep on the sand; sometimes half buried.  Some have been acclimated to aquarium food, however it takes persistence.  They are similar to the Green Spotted Mandarinfish which is smaller, pale green to green with dark green circles all over the body that have thin orange, green and turquoise edging.  The Red Mandarinfish has the same striping pattern as the Mandarinfish, however there is much more red in the body and little electric blue coloring. 

Mandarinfish can be very difficult or quite hardy, depending on the preparation of the aquarist.  They are best kept by intermediate to advanced aquarists who can understand their specific needs.  Mandarins are almost immune to Crypt because of their scaleless body and if fed well will live a long life.  Because of their scaleless bodies, do not use copper or Organophosphates (See list under diseases).  Do not add them to a sparsely fed tank, since copepods and amphipods will not have enough to eat and will not breed in the numbers needed to provide food for your Mandarin.  Avoid netting them, as their cheek spines will become entangled and can cause injury.  

Male and female pairs will often spawn in captivity.  They can be kept alone or in a male/female pair because 2 females or 2 males will attack each other unless the tank is very large.  Most fish will ignore the Mandarinfish due to it’s “leave me alone” coloring, however inverts such as potent sea anemones found near the bottom of the tank, elephant ear anemones, Elegance Coral (strong sting), large crabs, aggressive fish and mantis shrimp will eat them.  These are peaceful, slow moving, methodical eaters which will be outcompeted for food by wrasses from the Halichoeres (huge pod eaters) or Pseudocheilinus genus (lined wrasses).

Make sure your tank has 75+ pounds of established live rock (not base rock) for each Mandarinfish.  This rock should be seeded well with a good copepod/amphipod population before adding the fish.  These tiny crustaceans will be visible on the rock and the tank should be established (6 months or more).  Provide sand for the substrate for them to hunt and sleep on.  Some aquarists have used a ‘pod pile,” which is a few small rocks that are piled up tightly enough to protect most of the pods from predation.  Added to the middle of this pile would be a small piece of shrimp or food every few days so the pods will rapidly breed and come out to be eaten!  You can also add a refugium to the tank to keep the pod population up or culture your own pods.  

Scientific Classification

Species: splendidus

Mandarin Fish – Quick Aquarium Care

Aquarist Experience Level:Intermediate
Aquarium Hardiness:Moderately Difficult
Minimum Tank Size:55 gal (208 L)
Size of fish – inches:3.1 inches (7.87 cm)
Temperature:72.0 to 84.0° F (22.2 to 28.9&deg C)
Range ph:8.1-8.4
Diet Type: Carnivore
Image Credit: 22August, Shutterstock

Habitat: Distribution / Background

The Mandarinfish, Synchiropus splendidus, was first described by Herre, in 1927.  The genus name, Synchiropus is Greek for “grown together hand and foot.”  While the official common name is Mandarinfish, whose coloring resembles the robes of an Imperial Chinese Officer (mandarin), many other names they are known by in the retail world and hobby world.  These are Psychedelic Fish, Green Mandarin, Mandarin Dragonet, Striped Mandarin, Red Mandarin, Mandarin, Spotted Mandarin, Blue Mandarin, and Mandarin Goby.  

Mandarinfish are found in the Western Pacific from the Ryukyu Islands to Australia in shallow protected lagoons and inshore reefs over silty bottoms that also have coral and rubble.  They are found in small groups, though spread out over a small territory.  The depths they are found are from 3 to 59 feet (1 to 18 meters), feeding on small benthic crustaceans such as various amphipods and copepods.  

The Mandarinfish has not been evaluated by the IUCN Red List for Endangered Species.

Species Variations and Similar Species:

Although there are several fish from this genus of various colors, they each have a distinct look about them.  There is a variation of this fish where there is much more red on the body with very little to no blue, although they have a similar squiggly body pattern. 

  • Scientific Name: Synchiropus splendidus
  • Social Grouping: Groups – In the wild they are found in loose groups and come together to spawn once a week, 3 months of the year.
  • IUCN Red List: NE – Not Evaluated or not listed


The Mandarinfish has a greenish turquoise body with orange to deep orangish red, curving, maze-like bars that are finely edged in deep blue.  The face is green to orange and the chin area is pale green with the entire head having thin horizontally running electric blue lines.  These lines run across the face from eye to eye.  On the chin, they run along the length of the mouth and chin.  Their mouth is a tiny protrusion what is used to eat small crustaceans on sand, rock and coral.  The pectoral fins are electric blue with a slight transparency.  The pelvic fins have the same orange to deep orangish red as the bars on the body, or this color can be green on some specimens.  In both color variations (called green or blue) the pectoral fins have electric blue lines, bars and dots along with electric blue on the outer edge.  There are 2 dorsal fins, with the first one having a longer front spine for males.  Both sexes have that same body pattern on both dorsal fins.  Below and slightly behind their orange to red eyes is a small circular area that has lighter dots and dashes.  Some variations of this fish have a lot more red on the body with much thinner greenish turquoise bars, and they either have no electric blue on the fins if they are a true red variety.  There will be some blue if they are a mix between a red and blue/green.  When they sleep they become more pale. 

The males are larger, having a longer first dorsal spine, and can grow to 3.1” long.   Plan to provide for this beautiful creature for 10 to 15 years.

  • Size of fish – inches: 3.1 inches (7.87 cm)
  • Lifespan: 10 years – 10 to 15 years.

Fish Keeping Difficulty

Each Mandarin you keep should have 75+ pounds of live rock. The aquarium should be heavily populated with copepods and amphipods as well.  Purchase these fish as soon as they arrive at the store, avoiding any emaciated or very thin specimens.  Look at the area behind their pectoral fins, near the bottom of the body.  If that is pinched in severely, then pass on that one because it will probably not survive.  Some aquarists have had success placing a narrow glass bottle filled with pellets or mysis, that other fish cannot get into, on the bottom front of the tank to ensure they are getting enough food.  This can be done to train them to eat prepared foods, however the tank still needs to have plenty of copepods and amphipods for the long period of time it may take to wean them over.  They will still eat the live foods, so this is merely a supplemental feeding.   

While wild-caught Mandarins do fine in larger tanks, such as the one I personally kept nice and fat in a 150-gallon tank with a refugium attached, the captive bred Mandarins that are acustomed to pellets may not do so well in such a large tank.  A green captive-bred Green Spotted Mandarin starved in a 90 gallon that had plenty of copepods and amphipods.  It is thought that the fairy wrasses and other fish outcompeted the Mandarin for pelleted food that they were used to eating or they were too afraid to come out and “hid to death.”   Oddly, in my 150-gallon, the wild-caught Mandarinfish was skilled at foraging for live foods and did quite well despite other large fish such as tangs and even a tuskfish, so I would assume wild-caught are braver and were used to seeing other large fish!   That being said, wild caught will do well in bigger tanks, where captive-bred mandarins that are used to eating pellets will do better in a smaller tank with mellow tank mates that is around 29 gallons, so you can monitor their progress.  They still will need live rock with copepods!

  • Aquarium Hardiness: Moderately Difficult – If 75+ pounds of live rock loaded with copepods and/or amphipods is provided, they are moderately hardy.
  • Aquarist Experience Level: Intermediate

Foods and Feeding

Wild caught Mandarinfish, as well as captive bred are carnivores where they eat small crustaceans (and other benthic organisms). The latest on some of the newsgroups is that each one needs at least 75 pounds or more of live rock to survive. We have kept one in a 125 gallon reef that is doing fine and all he eats is whatever he finds on the rocks. With most fish variety is the key. Feed them anything they will eat and try lots of different things. Live brine, worms, formula I, and formula II, flakes, etc. The mandarin seems to only go for live food however. A mature aquarium with live rock really helps provide the natural food they need.

For your wild caught Mandarinfish, ensure there is a good population of copepods on 75+ pounds of populated live rock with more rock if there are other pod eaters in the tank.  Some wild caught can be trained to take pellet by adding a small jar that they can fit into with pellets for carnivores or mysis shrimp.  Monitor this jar and do not let the pellets rot.  For your captive bred Mandarin, per ORA’s website, “offer Nutramar Ova, finely chopped Hikari Frozen Blood Worms, fish roe, frozen or live baby brine shrimp, frozen daphnia, and New Life SPECTRUM Small Fish Formula pellets. Some have also shown interest in Cyclopeeze.”  Feed 3 times a day minimum, especially for your captive bred Mandarin in a smaller tank.

  • Diet Type: Carnivore
  • Flake Food: No – They typically won’t eat flake
  • Tablet / Pellet: Yes
  • Live foods (fishes, shrimps, worms): All of Diet – Especially for wild caught. Captive bred can eat prepared foods.
  • Meaty Food: All of Diet
  • Feeding Frequency: Several feedings per day

Aquarium Care

   Guidelines for water changes with different types and sizes of aquariums are:

  • Fish only tanks:
    • Medium-sized up to 90 gallons, perform 20% to 30% monthly depending on bioload.
    • Large Tanks 100 gallons and over, once water is aged and stable can be changed 20% to 30% every 6 weeks depending on bioload.
  • Reef tanks:
    • Medium-sized up to 90 gallons, perform 15% bi-weekly.
    • Large Tanks 100 gallons and over, once water is aged and stable can be changed 10% bi-weekly to 20% monthly, depending on bioload.

For more information on maintaining a saltwater aquarium see: Saltwater Aquarium Basics: Maintenance. A reef tank will require specialized filtration and lighting equipment. Learn more about reef keeping see: Mini Reef Aquarium Basics.

  • Water Changes: Bi-weekly

Aquarium Setup

Mandarins do best in larger reef tanks with at least 75+ pounds of good live rock per fish, loaded with copepods and amphipods.  Even captive bred Mandarins will need these natural foods and are said to do better in smaller tanks.  These fish can occupy reef tanks or fish only tanks, however fish only tanks should have enough light to provide the algae that copepods like to hang out and breed in.  Both will need a sandy bottom and rock work to hide in.  Temperature should range from 72˚F to 84˚F with a salinity of 1.023 to 1.026.  They can be housed alone or as a male/female pair, however there should be 150+ pounds of established live rock for a pair.  They do best in a peaceful community tank with a refugium to provide copepods or a regular addition of copepods and amphipods.

  • Minimum Tank Size: 55 gal (208 L) – Tank needs to be big enough to accommodate 75 to 150 pounds of live rock.
  • Suitable for Nano Tank: Sometimes – Only if mandarin is tank bred and fed 3 times a day with prepared food list (see list from ORA listed under foods)
  • Live Rock Requirement: Typical Plus Hiding Places
  • Substrate Type: Sand
  • Lighting Needs: Moderate – normal lighting – Enough to promote some algae growth that their natural foods like to live in.
  • Temperature: 72.0 to 84.0° F (22.2 to 28.9&deg C)
  • Breeding Temperature: 79.0° F – Summertime temperatures
  • Specific gravity: 1.023-1.026 SG
  • Range ph: 8.1-8.4
  • Brackish: No
  • Water Movement: Weak – Weaker near the bottom where they feed, however other parts of the tank can have stronger flow.
  • Water Region: Bottom

Social Behaviors

Mandarinfish are peaceful and can be housed alone or as a male/female pair.  Two males and two females will fight unless the tank is very large. 

While most fish ignore the Mandarinfish due to it’s “leave me alone” color, noxious slime, and sharp cheek spines, there are a few fish to avoid.  Scorpionfish, including Lionfish will not be deterred by their defenses.  Avoid soapfish as well as aggressive fish like the more aggressive triggerfish, large dottybacks and the more aggressive large angelfish.  Lined wrasses and Halichoeres wrasses will eat too many of the copepods that your 75+ pounds of live rock is housing.  I personally had no problem with fairy wrasses in a 150 gallon tank, however I had over 200 pounds of live rock, so that is probably why.

If housing in a reef, they will not bother any of the corals and will control Brown flatworm infestations.  Similar to some seahorses, certain corals should be avoided.  Stay away from strong stinging anemones, especially carpet varieties and elephant ear mushrooms.  Strong stinging LPS such as the Elegance Corals will kill them with their sting, and it will not be instant, but a long and painful death lasting a day or more.   

Inverts are safe, although they will eat a lot of copepods and amphipods.  Avoid large crabs and mantis shrimp.  

  • Venomous: No
  • Temperament: Peaceful – Will attack other Mandarins of the same sex.
  • Compatible with:
    • Same species – conspecifics: Sometimes – Only male/female pairs
    • Peaceful fish (gobies, dartfish, assessors, fairy wrasses): Safe
    • Semi-Aggressive (anthias, clownfish, dwarf angels): Safe
    • Threat
    • Large Semi-Aggressive (tangs, large angels, large wrasses): Monitor – Avoid Halichoeres Wrasses which will outcompete them for food. Other large wrasses should be okay. Monitor the more aggressive genus of Angelfish
    • Large Aggressive, Predatory (lionfish, groupers, soapfish): Threat
    • Safe
    • Anemones: Threat – Avoid the stronger stinging anemones and those that are near the middle or bottom of the tank.
    • Mushroom Anemones – Corallimorphs: Monitor – Elephant Ear mushrooms anemones and other fish eaters will eat them.
    • LPS corals: Monitor – Avoid the strong stinging LPS like Elegance Coral and similar.
    • SPS corals: Safe
    • Gorgonians, Sea Fans: Safe
    • Leather Corals: Safe
    • Soft Corals (xenias, tree corals): Safe
    • Star Polyps, Organ Pipe Coral: Safe
    • Zoanthids – Button Polyps, Sea Mats: Safe
    • Sponges, Tunicates: Safe
    • Shrimps, Crabs, Snails: Monitor – Avoid mantis shrimp and large crabs which will eat your Mandarinfish.
    • Starfish: Safe
    • Feather Dusters, Bristle Worms, Flatworms: Safe
    • Clams, Scallops, Oysters: Safe
    • Copepods, Amphipods, Mini Brittle Stars: Monitor – Will eat a lot of copepods and amphipods. Best to have a “pod pile” or refugium connected to the main display.
two mandarin fish
Image Credit: Makabas, Shutterstock

Sexual differences

   Males are larger and have a longer first dorsal spine.

Breeding / Reproduction

In the wild, for a few months a year, right before the sun sets, 3 to 5 females will gather in an area where the males are found.  Females can only spawn once per night.   Males will then display for the females, who by the way, greatly outnumber the females.   Once a male has won the heart of a female, she will sit on this pelvic fin and they will then move to a belly to belly position.  In this  position, they will raise together slowly to an area that is about 3 feet above the reef and at the peak of this rise, they will instantly release sperm and eggs (200 or more) and dart off into the reef again.  Interestingly, some small males will sneak up on the couple and release his sperm with hopes of fertilizing some of her eggs too!  The male will court several females in one evening.  The eggs will take 18 to 24 hours to hatch.  The 1 mm long larvae will remain as plankton for 2 weeks before settling into the reef. 

In captivity, the Mandarin couple will breed all year long.  Provide a separate tank for the spawning since the eggs will float until they hatch.  They will spawn once a week and this spawning act is regularly seen in captivity.

The following breeding information was contributed by Aaron in our guest book:

“Mandarinfish only spawn in the evening and exhibit very unique mating behavior. If a pair of them are healthy enough, they will begin spawning occasionally just after lights out.   The male and the female approach each other and begin to “dance” in a spiral up the water column. They release sperm and egg as they rise. The spawn are planktonic for some time, but will grow to a couple mm in length in a couple days.    If there are other kinds of fish in the tank, the spawn should be isolated. I know this info is relatively general, but I have not personally mated Mandarins (I only have a large enough tank for one fish).”

For more information about recent concerns as well as mandarinfish breeding habits check this article at National Geographic.

  • Ease of Breeding: Moderate

Fish Diseases

Mandarinfish are pretty much disease resistant, however they can fall ill due to suppressed pH or deteriorating water conditions.  This is true for any fish!  Starvation is usually the biggest killer of this fish.

Avoid using copper medications or Organophosphates (OPs).  The examples of OPs are dichlorvos (DDVP) and trichlorfons.  Trichlorfons degrade into DDVP when added to the water.  The three marketed names for trichlorfons are Masoften, Dipterex and Neguvon.  These medications are used to treat skin flukes, gill flukes, leeches, crustacean ectoparasites (fish lice) and anchor worms.  Most OPs have been banned in several countries, and these treatments are very sensitive to water temperature, making them less “user” friendly than less toxic drugs.


These fish are easy to find on line and in stores for $14.00 to $19.00 for a blue/green Mandarinfish or $59.00 to $99.00 for a captive bred or Red Mandarinfish.  (USD, 2/2015)

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Featured Image Credit: Synchiropus splendidus (Image Credit: Llez, Wikimedia Commons CC BY-SA 3.0 Unported)