Dwarf Angels are known to pick at soft coral. They don't eat it entirely, but every now and then pick. so they should be allright in the long run, with little to no damage depending on tank variables . clams could possibly be slightly problematic depending on type and hardiness. So if monitered, you shouldn't have that many problems. But variables such as tank size (bigger=less problems), hunger, and other fish presence affect your fish's outlook on these things. Summed-up you should be ok if small things like shrimps aren't present and you excerise caution at first while keeping it well fed. PS. I messed up the quick-reply options, so this is a response to nycbob, not a statement of my own.