well, yes aquarisol is safe. However, i dont reccomend it. What kind of parasite is it? For most parasitic infections, bacterial infections, ick, velvet disease, and etc. I would definetly recommend Quick-Cure. However if it is some kind of external parasite, like a little guy on the fish that moves around and stuff, i reccomend isolating the fish in somethin like a bowl, and try to scrape it of (gently.) this worked for me when my goldfish had a parasite. It sais quick-cure can treat this to so i would follow up with use of quick-cure. Let me know what kind of parasite it is, and i will help you the best i can!