you can use melafix and pima fix in the tanks just make sure you have air in there follow directions,on the bottle, treat the tank it won't harm bacteria, or the fish it works very well with finrot keeps everything so it can't grow and helps it heal and keeps the bacteria from getting in to the wounds..so no secondary infection, i have used it many times its all i use if you catch it in time you can treat it very fast, follow directions on bottle i use it in my 90g tropical tank with all kinds of cories and they do great, just make sure you have good airation,for it bubbles a bit at first. then water change the h*ll out of it after treatment to keep it clean so no one else gets it..it's all natural..