These two compatible?

Depends on the size of the tank for the Mandarin but yes they would be fine together. No reason they wouldn't be. Mandarins need a VERY established tank (don't place one in a tank under 6 months old but waiting a year or two is best) in order to survive and 55 is bare minimum (I actually think 100 is minimum but that's just me). Anyway, hope this helps and good luck.

Mandarins are safe with most reef safe inverts, and won't bother invert themselves. Make sure you can support their need for pods, or know for certain that it is taking prepared foods. I think keeping them in with just inverts for the first 6-9 months is best--no competition for food. Even then, lots of live rock, and everything you can do to increase the pod numbers, will be best, and maybe not enough.