Dekalb08,
I'll address safety, as aesthetics are up to you.
Hydrated lime is very harsh. If you make a white cloud of hydrated lime in the water, any fish the swim through it will be killed quickly or at least stressed and some may die later. That's why it's important to keep the mixture area as small and isolated as possible. Try to do it in an area that has little cover and few fish. You can splash and stomp around and scare them away from the cloud. I've applied several bags carefully, and only killed a dozen or so fish. I find that an acceptable trade off, but it also killed tadpoles, crawfish, shrimp, etc.
Alum is not nearly as harsh as hydrated lime. I've noticed that it freaks the fish out and makes them jump sometimes, but I've never seen a floater. It's still advisable to keep the the rich mixture area as small and isolated as possible. Alum mixes very readily with water (about as easy as dissolving sugar or salt), so that's not a problem.
