It would help to have a bit more information about your tank. How long has it been set up? Have you tested your water? What are the parameters?
I had guppies in with my Zebras and never saw any interaction at all. I personally would be surprised if your Zebra was responsible for attacking the guppy or the glowlight. I did, however, move the guppies because the tank just wasn't suitable for them (too warm) and they didn't do well.
When you say your fish are injured, can you describe what has happened? That might help too.
