What looks like flatworm?

[synofreak]

I recently purchased an Angel(emporer)......had a small amount of fin rot. Set up the QT with Furan 2. FW dip has him "releasing" organisms that appear like flatworms, small and whitish.

Might this be the right treatment? Said organisimz died and removed upon FW dip. He is in furan 2 now, but I can setup my other QT if need be.

Thanks for help.......want to treat it right.....