is growth on goldfish normal?

My goldfish are recovering from what I diagnosed as a bacterial infection
(did water changes and medicated with Tetracycline (recommended by LFS)),
but now there's some growth from where the red spots were before. Is this
normal? I took a closer look at the growth (kinda looks like a strand of
hair) and was wondering if i should try and remove it or leave it alone.
The fish are very active and don't seem bothered by the growth.