They are supposed to be poisonous, probably to eat, but I have plenty of fish picking at the decaying edges of some of the leaves and the fish are all long lived and fine for years now. I have trimmed and broken off pieces of A. large and small and even in my shrimp tank.
But just to be on the safe side I would do a pwc a few hours after the trim, and maybe a couple over the few days afterwards just to be sure. I have made sure to do the pwc if I cut them. for that reason, just in case! Rarely have had to trim as they aren't super fast growers