They do alright in reef tanks as long as you don't have any clams. They are known to much on the mantle when they're bored, hungry, or otherwise unoccupied.
people have said you can only keep one type of a dwarf angel in one tank/ reef
i have 14 different kinds.. the Flame Angel is one.. this pic is not of mine but but this is a flame for the person who asked , my dwarfs never have hurt my corals in any way in 5 years...
Flame Angels will not harm or eat soft coral and id a fairly reef safe fish, but on exeption if hungry and not been fed for 2-3 days they will start attacking softer corals and smaller invertabrates.
I have a Flame Angel, Coral Beauty and Half Black.... They pester the clams and softies, but nothing terrible, I wouldnt worry about it. But, one never knows how they will act until they are in the tank.
When fed regular and watched they can be reef safe. They are not 100% reef safe, but there are many being kept with corals with no problems. Angels are awesome and the Flame is one of the real beauties.