The Mandarin Fish


There are some spectacularly coloured marine fish and the mandarin fish must surely rank very highly among these. It’s a dragonet and the proper name is Synchiropus splendidus. There is another fish that competes for glory called the psychedelic fish properly called Synchiropus picturatus, the markings are generally circular. If I were to be the judge, the mandarin would take the crown.

The mandarin can grow to about 4 ins (10 cm) but is likely to achieve less in an aquarium. The environment needs to be of high quality as is always the case – for this fish it means high quality sea water in a reef system. The fish is not suitable for a fish only aquarium. There should be many rocks which afford many caves and crevices for the fish to hide in. The fish is not particularly secretive but needs suitable décor for security. Only one fish should be kept as two could cause trouble – two males are likely to fight. Advanced aquarists with a suitable large very mature reef system could cautiously try a male and female, the sexes are determined by the male having a first ray on the front dorsal fin twice as long as the female’s. The fish are reasonably tolerant of light from subdued to fairly bright.

It’s very sad that these fish are often bought by inexperienced aquarists and they are then for the most part doomed. Inexperienced aquarists should not obtain this fish and should resist the beauty of it. Even if the aquarist has a reef system that has been properly initially matured and other fish are healthy this still will not do. The problem is adequate feeding.

The mandarin fish spends most of the day moving about on the surfaces of rocks, algae and sand looking for food which consists of tiny organisms. Therefore the fish has a very small mouth. It could be, though it isn’t the norm, that the aquarist will find the fish will take some brine shrimp but in the longer term this will be inadequate. This is why the fish must be housed in a reef system so that it has the best chance of finding proper nourishment and the larger the reef system the better as the possibility of finding food increases.

So the guidelines are first and foremost do not buy a mandarin on impulse! Second, the aquarist should have some experience – it’s difficult to put a time period to this but say more than a year and seawater quality is continuously high. Third the fish must have a reef environment though this does not guarantee that there will be enough food whatever the reef size. Finally the aquarist must be willing to spend some more money to try to ensure the mandarin is properly fed.

Spending even more money to feed one fish? If a higher chance of success is required then yes. As already said even with a large and very mature reef system there isn’t a guarantee that the proper food will be available in sufficient amounts. A proper diet in sufficient amount is important to all life forms. So it will be necessary to spend some extra money at least at first and possibly continuously.

 Nowadays the marine hobby is very well supplied by the marine industry and this applies to food types. Available nowadays are ‘copepods’ which can be put into the reef system and on which the mandarin can feed. It’s necessary to monitor the amount required as far as possible (this is done with food for all fish anyway) and it could be that the amount added will diminish as time passes. Once the mandarin is in the aquarium and appears reasonably settled because it is looking for food, put in a batch of copepods. Observe for a week and then put in a second batch and again observe. The mandarin should be seen to eat as it ‘pecks’ at the rocks etc. If all seems well place more copepods in but this time after two weeks. If the mandarin appears to be finding food throughout this period leave another week (that is a period of three weeks) before considering a further introduction of copepods – and so on. Hopefully the introduction of food will be very much reduced as the aquarist finds an adequate introduction rate.

 The addition of copepods to the aquarium has the additional benefit that the tiny creatures generally are detrivores eating leftover food etc. When adding these to the reef system it’s a good idea to add a small portion to the sump if there is a deep sand bed.

 The mandarin fish (and the psychedelic fish) are wonderful additions to a mature reef system, but only if the aquarist is willing to give the fish the best chance of health. This of course applies to all aquarium life but particularly so to some specialist feeders. If the aquarist pays the price for success, the price being observation and expenditure on food as required, then the mandarin will remain in good health for a long time.  


  1. I really appreciate your post on the Mandarin and other dragonettes. Too often they are purchased on impulse, like you said, because they are so beautiful and captivating. Way to go.


  2. Hello Warren. I’m glad you enjoyed the post and agree with the major danger to Mandarins.

  3. Hey Folks, With the amount of care these fish need i would hope that the Pet Store selling the fish would stress the care level to the hobbyist. Great Article! Happy Reef…

  4. Hello Jeff. It’s more than unfortunate that some fish stores are ready to sell to anyone. This is understandable as the store relies on sales for survival of course. However it’s a negative for the future of the store I would think as once the customer gets more experience he/she will go elsewhere for ‘proper’ attention. Having said all that there are some really good stores as well who clearly care for the livestock and for future business.

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