is melafix safe for me?

Why do you want to use it? Melafix contains Pimenta racemosa, which is an extract of the Bay Rum Tree. Some studies have shown it to have some antiinflammatory properties (kind of like fish motrin) but it's effectiveness as an anti-bacterial or anti-fungal are not quite as proved. Depending on what you're treating, IMHO, you may be better off using an appropriate antibiotic rather than relying solely on Melafix.

Pimafix contains Pimenta racemosa.

Melafix contains Tea Tree Oil from Melaleuca cajeputi, M. leucadendron and "other" Melaleuca species.

Both are made by Aquarium Pharmacuticals, inc.

They work independently and together.

Sorry, I can't answer You question about those fish.

I stand corrected. I have a tendency to mix the two up as I really don't use either one.