I dont know fish disease and meds. Its up to you to do some research now. If you want to easily feed for gsp, then go buy frozen raw shrimp, mussel, cockle, clams, etc. Thaw in a cup of tank water. You could even add Seachem's vitamin water during the thawing period as cheap insurance for your fish to get all of its vitamins.
Setup another tank with refugium in the very near future. There are a lot of expense and work ahead of you.