Any angel can work but the vast number of individual fish will sample something sooner or later. By large angel I am assuming you mean a pomacanthus or holocanthus? These are all pretty risky especially with LPS and clams, I agree the genicanthus are the best bets but I had read stories about geni's eating LPS as well. If you like the Bellus I would go for it, it's one of the safest bets of all the angels.