Mandarins are commonly found around the Philippine Islands but their range extends westward to western Australia (Achterkamp 1986).

On the reef, they can commonly be found in small groups, or in pairs, and are closely associated with sandy areas between reef crests (Achterkamp 1986). The typical coloration of S. splendidus consists predominantly of orange wavy lines on a blue background, the dominant color is blue, but there are also orange, green, purple and yellow present. The bizarre color patterns have to be seen to be believed.

In the aquarium this species has often been referred to as delicate or difficult to keep for the average hobbyist. They do best in aquariums with peaceful, non-aggressive fish or at least in larger aquariums where the more boisterous members cannot disturb them greatly. They are sensitive to water quality and tend to be rather finicky feeders. In recent years, the advent of reef-type aquariums, utilizing an abundance of live rock and plants, appears to have increased the chances of success with this beautiful fish, indeed, tank spawnings are becoming commonplace.

Mandarins tend to be rather picky eaters, preferring to feed from the bottom. Due to the relatively small size of their mouth they must be fed only small food items or finely chopped foods. As mentioned above they appear to do much better in aquariums with abundant live rock and/or plants. This may be due to the fact that there is an abundance of natural food items for them to feed on. In such an aquarium they will spend most of the day grazing amongst the substrate searching for food items such as small crustaceans (e.g. Mysids, amphipods, isopods and benthic copepods), small worms and protozoans. If you have a well stocked reef tank you will probably never have to give any additional feedings to your Mandarins. If you do decide to try additional feedings you can try baby brine shrimp, frozen/live Mysis shrimp or adult brine shrimp. In some cases it may help to turn off you water pumps and filters such that the food can settle to the bottom first so that the fish can get to them. If your Mandarins are housed with larger, more aggressive fish, they will not get to the food in time. In any event, keep in mind that Mandarins are not big eaters so any additional feedings should consist of small quantities of finely chopped foods.

Mandarin fish lack scales and instead have a rather thick, slimy, mucus coating on their bodies. This coating tends to make them rather resistant to parasitic skin diseases. If a Mandarin does get sick DO NOT use any heavy metal based medications (e.g. copper sulfate). Such medications cause an increase in body slime production and the fish can literally suffocate in their own body slime (Achterkamp, 1986). In fact, this holds true for most scale-less fish such as gobies and blennies.

Mandarin fish are one of the few marine tropicals which can be easily sexed. There are a number of morphological features which can be used to differentiate between the sexes. The males tend to be larger and more robust than the females. The caudal and soft dorsal fins are larger in the male and the male tends to have more orange on it's face. However, the most distinctive difference is in the dorsal fin. The males have a greatly elongated first dorsal spine while females do not. In fact, in some males this dorsal spine is long enough to actually reach the base of the caudal peduncle when laid flat. During the day both males and females will display a total lack of interest in each other, however, just before the tank lights go off or shortly afterward, the male will search out the female. They will then slowly circle each other while rising in the water column. When they reach the apex of their "dance" the eggs and sperm are simultaneously released into the water and the pair then return to their separate ways. This type of behaviour can occur almost every night for several months. Since the eggs are planktonic they must be collected immediately before they are filtered out or eaten. The eggs hatch within 18 hours and the larvae are approximately 1 mm in length with a predominant yolk sac. The larvae remain planktonic for at least 2 weeks before they begin orienting to the substrate. Mandarin larvae are extremely small and cannot be fed rotifers as a first food but success has been achieved through the use of marine in fusoria and especially copepod nauplii (Julian Sprung, personal communication). Others have reported success with rotifers as a first food and it may be that the particular strain of rotifer (i.e. size differences) used is an important factor.

Finally, when purchasing new specimens pay careful attention to their bellies. They should not have sunken bellies as this is an indication that they have not been feeding for some time. Mandarins should be acclimated in a separate container from any other new arrivals since they can produce copious amounts of slime which may affect other fish in the same container (Achterkamp, 1986).

With the advent of reef aquariums, and improved collection and shipping techniques, these living jewels of the reef are becoming more commonplace in the average hobbyist's aquarium.