Something to fix damaged fins?

[MMAX]

Anyone know of anything (medication or other) that will repair damaged fins and tails on fish? I had two very agressive angels that I thought were eating the fins of my silver dollars and arowana. I got rid of them a few weeks ago but haven't seen any improvement. The silver dollars are missing some big chunks out of their tails and the arowana's top and bottom fins and tail are almost totally gone and badly frayed.