Do yourself a favor and DO NOT do that H202 treatment. You have some very nice fish and there is a good chance you will lose some of them. It's not worth it to get rid of algae. That thread is littered with people who have lost a lot of fish because of that treatment.
Depending on your stocking, it may be easy to remove your fish and put them in a temporary bucket with some tank water and your filter media. I've done that once before, and it certainly removed the stress of worrying about hurting them.