I think it would probably be best for it to stay in the 75g since it is such a big fish. However I definitely see where you are coming from with being concerned about contamination.
I'm looking at the
Seachem website and their available medications and Paraguard is looking like a good catch all type medication. You can click on the link to see all the medications. I'm pretty sure its widely carried but I'm not too sure about that.
What is the triggers behavior like now? Still hiding?