I kept a few male Mandarins Gobies in 55 and 40-gallon soft coral display tanks for several years without any problems (one at a time). I gave them weekly feedings of live brine shrimp at first, then slowly introduced frozen brine, live and frozen blood worms, Vibragroâ"žÂ¢ and Cyclop-eezeâ"žÂ¢ to their mix of live food.
I keep live food in the ‘frig and stretch feedings out over most of the week. I fed in two corners â€"œ one where the other fish gathered, and one where the Mandarin was hanging out, to make sure the Mandarin got some. It seemed that once the Mandarin saw the other fish eating the food, he would try it also.
With a 2-gallon mud-based, algae refugium on my 40-gallon soft coral displays, I did NOT need to feed live food at all. Though the refugium was crawling with little white bugs, I never saw any copepods in the display. The Mandarin was always busy picking at the rocks.