The Mandarin Dragonet (Synchiropus splendidus) can simply not be confused with any other fish. It has arguably the most attractive coloration and pattern of any commonly kept reef fish. The scale-less body of the fish is a blue or green color which has orange wavy lines across it. The tail is bright red with blue edging. Other colors can be found in the pattern as well. These fish are also sometimes called Psychedelic fish due to its rather bizarre coloration. The male Mandarin tends to be larger than the female and has a large pointed dorsal fin that is only occasionally displayed.
Mandarin Dragonets are one of the more commonly sold fish, yet they are unfortunately one of the most likely to perish in the average reef tank. The reason for this is their very finicky feeding habits. Most Mandarins will only eat live copepods which are found in sufficient numbers only in larger and well established reef tanks. The minimum tank requirement is generally stated as 55 gallon with 50lbs or more of live rock. This is based on feeding requirements and not space requirements as the Mandarin is a very slow, docile fish. Perhaps more important than tank size is how heavily fed and nutrient rich a tank is, since this type of tank will generally support a higher pod population than tanks run under more lean conditions.
If you are able to get a Mandarin Dragonet that is feeding on frozen food, they can be an excellent candidate for a small tank since they are small, slow moving fish.
More often than not Mandarin Dragonets are kept in conditions in pet stores where there is no opportunity for them to feed and therefore are under starvation conditions. A healthy, well-fed dragonet should have a full body and a nice rounded belly. If it looks shrunken in, the fish has not been feeding for some time and it is difficult for the it to recover from this state even when placed in a tank with adequate food.