The Spotted, or Psychedelic Mandarin
The Green Mandarin
Mandarin fish are some of the most beautifully colored fish in the aquarium hobby. These fish are definitely reef safe, will get along with most other inhabitants in a tank, and have a relatively small price tag. However, Mandarins are one of the most challenging fish to keep. They are not very hardy and their diet is composed primarily of copepods, which are small crustaceans that are grown in the tank. There have been reports of people who have gotten their mandarins to eat dry food pellets and flakes, but it is rare.
Mandarin fish are not for the inexperienced reef keeper. These fish require a lot of rock work and a well established tank. It is not recommended to introduce this fish to a system less than 1 year old. The reason being copepods need time to grow and multiply in a tank to have enough to keep the mandarin fed as well as be able to sustain a decent sized population so they can keep reproducing. Although these fish take some care when it comes to feeding, these fish are normally hardy given that good water conditions are maintained. Also, most fish in the dragonet family are disease resistant, but if not kept in the right system can exhaust the supply of copepods very quickly, causing them to either starve themselves or become weak and die.
If this is a fish that you really want, there are a few things you can do to help it. The first thing that you may want to look into is a refugium. A refugium is a small add on tank which you can use as additional filtration with live rock and macro algae growing inside. This tank can also be used to grow copepods that will be sucked through your return pump and put into the main display tank for your mandarin and other fish to eat. This is a relatively inexpensive option compared to buying an acrylic sump for filtration in your tank and is HIGHLY recommended for reef tanks. There are also many articles about how to build a refugium if you are good at do-it-yourself projects.
The next thing you can do is use store bought copepods and other small crustaceans to refill the population in your tank. You would only need to do this once every couple of weeks to a month.