I'm by no means an expert on SW tanks. However, I have a Mandarin Dragonet that is doing very well in my 90g tank. It's actually improved its health since it first arrived at my home. It's fatter and swims frequently. Though I may have lucked out because mine has no aversion to frozen brine shrimp (must be thawed first). I do not think these fish are difficult to keep if the hobbyist does proper research before purchasing one and has a tank of the right size with plenty of LR. Of course, imo every fish should be researched before adding them to the tank.