If you are going to rescue fish i would highly reccomend a full quarentine before adding fish to your main tank. Neglected fish are often riddled with infections and parasites. Its a good thing to want to help them out but don't risk the health of your current stock. Quarentine will save you money and heartbreak in the long run. Just a heads up from some one whose been doing it for a minuet. Good luck with them dear.
So its been a while now and fish are doing great, i went through hell to cure these guys but they are doing great, the gt had internal parasites ,(rebuilding his belly, now), i treated the whole tank with a course of api general cure n garlic marrinated food mixed with a little of api general cure. I also had to deal with fin rot on the gt. The gt still has a a fair way to go before im satisfied with his health n looks but hes on the road to gettin there and has improved a lot. Ive got a tiny fungal infection left which im treating with pima and melafix (small doses over time with weekly 25% water changes.)
P.s. the gt was male, its fins n colors were in such bad shape before, we thought it was a she...