I love the idea, can't wait to see it progress. I think a large school of angel fish in this would look amazing.
Or have you thought about some larger fish to protect your tank? I think an Oscar would be awesome. 75 gallon would be great for a big ol' black male oscar to protect your forest! Or even a white one
I've never owned one myself but when I go to my LFS I find myself staring at them the longest because they seem to be the smartest aquarium fish and you can really tell they're thinking about things.