There are two types of fixer: hardening and non hardening. Both could be used for film and for paper. Hardening, as the name suggests, is making the gelatin harder and more scratch resistant, but some says it hampers washing and any treatment after fixing like intensification or reduction, hypo clearing or toning. I use Hypam from Ilford, which is non hardening, cause once is cheaper and second leaves the options open. I think for you it is really not that important right now. Use what your local store has on the shelves. And yes, same fixer for both, it might be just in different dilution. Read the label.