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Related FAQs: Psychedelic "Gobies"/Dragonets/Mandarins & their Relatives 1, Mandarins 2 , Mandarins 3Mandarin Identification, Mandarin Behavior, Mandarin Selection, Mandarin Systems, Mandarin Compatibility, Mandarin Feeding, Mandarin Feeding 2, Mandarin Disease/HealthMandarins/Blennies/Gobies & Crypt, Mandarin Reproduction

Related Articles: Gobies & their Relatives,

/The Conscientious Reef Aquarist

Mandarins, Psychedelic "Gobies", Dragonets, Scooter Blennies....YAH! Family Callionymidae

By Bob Fenner

 Synchiropus ocellatus

Often going by the common name "gobies", the Dragonets actually occupy an adjacent Suborder (the Callionymoidei). "True" Gobioids vary from them in a few obvious ways: placement and shape of pelvic fins (anterior to the pectorals in Callionymids, posterior and suction-like in Gobioids), the opening of the gills (small apertures up behind the head in Callionymids, larger in gobiods) .The fourteen genera and about 186 species of the family Callionymidae are typified by small gill openings, by having broad, depressed heads, and scaleless bodies with two dorsal fins... Living on the bottom with a characteristic "scooting" type of locomotion. 

The predominantly offered genus is Synchiropus. Synchiropus splendidus is the Blue, and Synchiropus picturatus, the Green or Spotted Mandarin. These two have one of the most dismal survival records of captive marines. Almost all perish within a month of wild capture... most often due to simple starvation.

Selection:

The principal selection criteria for picking out healthy dragonets are their fullness of body and activity level. Suitable specimens should not be skinny, and should be out and about, investigating their environment. For sure you want to see the specimen/s eat.

Selection:   (Andy Bulgin input/corr.) The principal selection criteria for picking out healthy dragonets are their fullness of body and activity level. Suitable specimens should not be skinny, and should be out and about, investigating their environment. For sure you want to see the specimen/s eat. [If the specimen/s is not actively hunting for food and/or is skinny, do not buy it.]

 

Above, an okay "index of fitness" Green/Spotted Mandarin and one that is too characteristically thin (note, "line" along body midline). 

Habitat:

Some species of mandarins offered in the trade are found on nothing other than sandy bottoms, but the Green/Spotted and Blue/Psychedelic species are almost always located in and amongst (mainly Acroporid) coral rubble, which they only venture out past sunset to feed and interact with their own kind.

Foods/Feeding:

As stated over and over, feeding, or rather a lack therein is THE common cause of loss of these animals. They spend many hours seeking out small live invertebrates living in/on live rock and substrates. If these are not present or otherwise supplied, you will see your mandarins sides sink in and its vigor wane. Live foods can be bought on a regular basis, cultured in separate vessels, in an attached fishless refugium. Starter cultures for these organisms can be purchased from companies that you can find on the Internet using the search terms: "live plankton fish food".

Do not fall into the trap of offering nothing but adult live brine shrimp, suffused with supplements (e.g. Selcon) or not. It's not unheard of that a dragonet will accept (with training) frozen/defrosted foods in place of live, but it is rare that non-live foods sustain them.

Disease:

Dragonets are notably slimy fishes that are not as susceptible to external parasite infestations as other fishes. However, they are not immune, and are overly sensitive to copper compounds, other metal-based and formalin containing medications. They are best treated through environmental manipulation (hyposalinity, elevated temperature) should they show signs of such afflictions.

Disease:  (Andy Bulgin input/corr.) Dragonets are notably slimy fishes that are not as susceptible to external parasite infestations as other fishes. [For this reason, and because the typical quarantine setup lacks the live food necessary to sustain these animals, the quarantine of visibly healthy specimens is best skipped altogether in favor of an extended pH adjusted freshwater dip/bath.] However, they are not immune to disease/infection, and are overly sensitive to copper compounds, other metal-based and formalin containing medications. They are best treated through environmental manipulation (hyposalinity, elevated temperature) should they show signs of such afflictions. Andy

Foods/Feeding/Nutrition

Whatever other writers have stated, Mandarins almost never accept enough of anything other than live foods that are omnipresent in their system to sustain themselves. A nutrient rich live rock reef tank, read that as one heavily populated with hard substrates, with substantial interstitial crustacean and worm, and other small sessile invertebrate life of about 100 gallons will support one individual. And this assumes you have no similar food-competing tankmates.

In the wild their food choices are principally small crustaceans and worms. You can culture these "incidentally" in a large main/display system with lots of substrate and/or live rock, but adding a live fishless refugium will go an immense distance in assuring your mandarin/s receive sufficient live food. These fishes cannot live on dried-prepared or frozen/defrosted, or chopped meaty foods.

Compatibility

Callionymids are very docile when it comes to competing for food or space and must need be kept with other very easygoing fish species or perish from harassment or lack of food. Also overly aggressive invertebrates should not be mixed with them. Dragonets are good reef aquarium specimens, leaving alone all desirable species, but may in turn be consumed by anemones, the large coral anemone (Amplexidiscus), or large crustaceans. Ideal tankmates include tube-mouthed fishes (seahorses, Pipefishes), small blennies, Jawfishes and gobies, Dartfishes, flasher and fairy wrasses. Larger wrasses, Dottybacks, goatfishes, most butterflyfishes, angels and puffers, triggers are definitely out.

Though seemingly defenseless in their slow swimming and "scooting" locomotion, this group of fishes is widely unpalatable… some evidence exists that their body slime is toxic or at least unpalatable. This and a prominent gill cover spine serves these fishes well as predator deterrents in most cases. A related note re this opercular spine; take care to scoop out mandarins with a bag or specimen container rather than a mesh net, as these can get fouled easily with the protuberance.

You may well see them kept in a group at a dealers but be warned, this is not a natural setting, and all species should be kept either one to a tank or as a single male with more than one female or a heterosexual pair. Otherwise, unless the tank is very large (hundreds of gallons) eventually you will see them fighting vigorously.

Reproduction:

For species known, Callionymids are pelagic spawners that come out past sunset, "do a formalized dance" and release their gametes into the environment, where they float up into the moving upper water column via currents. Spawning occurs at about weekly intervals (Algosaibi 1983), eggs are released of a few hundred in number, approximately a half to one millimeter in diameter, that hatch out in about a day. Depending on species, young remain in the plankton from a week to forty days before settling down. Unfortunately no young have been raised to date.

Though far less frequently imported, males are easily distinguished from females by much longer (about three times the length) first dorsal fins, larger size and brighter coloration.

Some of the Few Dragonets Seen in the Trade:

Most dragonets are rather bland in coloration, a smattering of brown, black, yellows… but a few are spectacular "paisley" prints. All are comical in their behavior.

Dactylopus dactylopus (Bennett 1837), the Fingered Dragonet. East Indo-Western Pacific; on sand and mud bottoms, to 50 meters depth. To 18 cm. in length. N. Sulawesi pix.  http://www.fishbase.org/Summary/Species Summary.cfm?ID=8240&genusname=Dactylopus&species name=dactylopus


Bigger PIX: The images in this table are linked to large (desktop size) copies. Click on "framed" images to go to the larger size.

Verticals (Full/Cover Page Sizes Available
Dactylopus kuiteri Fricke 1992, the Orange-Black Dragonet. Western Central Pacific: Indonesia. To six inches. This one in Raja Ampat.

Bigger PIX: The images in this table are linked to large (desktop size) copies. Click on "framed" images to go to the larger size.

Genus Synchiropus:

Synchiropus ocellatus (Pallas 1770), the Ocellated Dragonet, THE Scooter Blenny. To three inches in length. Western Pacific; Japan to Marquesas. Live on sandy lagoon bottoms. Below: Aquarium images and one in Nuka Hiva, Marquesas, Polynesia, where this species is very common. http://www.fishbase.org/Summary/SpeciesSummary.cfm?ID=7981&genusname=Synchiropus&speciesname=ocellatus
Synchiropus moyeri Zaiser & Fricke 1985, Moyer's Dragonet. To seven and a half cm. West Pacific. Raja Ampat photo of a half inch juvenile.  http://fishbase.org/Summary/
speciesSummary.php?ID=27030&genusname=
Synchiropus&speciesname=moyeri

 

Verticals (Full/Cover Page Sizes Available)
Bigger PIX: The images in this table are linked to large (desktop size) copies. Click on "framed" images to go to the larger size.
Synchiropus picturatus (Peters 1877), the Green, Picturesque or Psychedelic Mandarin/Dragonet. To seven cm. Indo-West Pacific; Philippines, Indonesia, northwestern Australia. Aquarium photo.  http://www.fishbase.org/Summary/SpeciesSummary.cfm?ID=12740&genusname=Synchiropus&speciesname=picturatus

 

Synchiropus splendidus (Herre 1927) the (Splendid, Blue) Mandarinfish. To 6 cm. in length. Western Pacific; Ryukyu to Australia. Aquarium photo. There are some red-based individuals. Spawned, rearing records exist for captivity.  http://www.fishbase.org/Summary/Species Summary.cfm?ID=12644&genusname=Synchiropus&species name=splendidus


Bigger PIX: The images in this table are linked to large (desktop size) copies. Click on "framed" images to go to the larger size.

Synchiropus stellatus Smith 1963, the Starry Dragonet. Western Indian Ocean: northern Mozambique to Sodwana Bay, South Africa. Also around oceanic islands. To 3 in. overall length. Aquarium photo. One of the newer, more readily available species in the family. http://www.fishbase.org/Summary/SpeciesSummary.cfm?ID=7802&genusname=Synchiropus&speciesname=stellatus

Cloze:

So, let's review. To successfully keep dragonets one needs a very peaceful, large reef system with lots of live rock and deep sand bed and/or such a system with a vibrant fishless refugium (highly recommended). Don't have this sort of set-up? Leave these fishes in the ocean. 

Bibliography/Further Reading:

Algosaibi, Farouk A. 1983. Spawning mandarin fish, Synchiropus splendidus (Herre). FAMA 5/83.

Bartelme, Terry D. 2001. Caring for a Mandarin. FAMA 6 & 11/01.

Carlson, Bruce A. 1983. The mandarin fish Synchiropus splendidus (Herre). FAMA 2/83.

Cuttriss, Alastair M. 2001. The Mandarin dragonet. FAMA 4/01.

Debelius, Helmut. 1987. Mandarin dragonets in the marine aquarium; spawning at night. Today's Aquarium-Aquarium Heute 1/87.

Delbeek, J. Charles. 1989. The mandarin fish: Synchiropus spendidus (Herre). SeaScope Fall 89.

Kurtz, Jeff. 2000. Synchiropus: Dragonets with style. FAMA 5/00.

Lang, Tom. 1998. Care and feeding of the Mandarinfish (Synchiropus splendidus). Aquarium Frontiers 1/98.

Mayland, Hans J. 1975. The Mandarin. Marine Aquarist 6:3/75.

Michael, Scott W. 2000. The dragonets. Beautiful, but not for everyone. AFM 9/00.

Michael, Scott W. 2001. The very common problem of feeding mandarin dragonets. AFM 11/01.

Sprung, Julian. 1994. "Reef Notes". FAMA 8/94.

Stratton, Richard F. 1998. Secrets of the exotic mandarinfish. TFH 3/98.


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