First off before you use a medication like copper, make sure it is ick. Once you are sure, start right away, sooner the better. If you have any inverts, remove them to qt, make sure they have something to eat. You want to use cupramine by seachem, go to their website and get detailed instructions on how to use it. Keep your skimmer running if you have one, you may need to make some adjustments, but you will remove any carbon, chemipure, etc. The cupramine will not kill your biological filter but get the seachem ammonia alert badge to be safe. Dosing will be tricky because your rocks and substrate will absorb the product. Get the seachem and/or salifert copper test kit, I use both because I'm ocd. Estimate the water volume as close as you can, not the tank size, in the end it will take more product than recommended because of the rocks and substrate. Dose 1/2 dose then next day test the level of copper, you'll find that it will be lower than you expected. Dose another 1/2, next day test again. Continue until you reach therapeutic level. Depending on the amount of rocks, substrate you have will depend on how much more you will have to use. Always test before you add and try and calculate the results of each dosage. Once you get to therapeutic level, stop dosing and it will somewhat level off; you may need to make very slight adjustments after that. Be ready to do water changes if ammonia alerts or you od the cupramine. Topping off and any water changes will lower your level and it is very important to maintain a constant consistent therapeutic level. Test daily and keep therapeutic level throughout, I do 3 weeks. At the end of the 3 weeks, do your water change then I run cuprizorb, again go to seachem's website for detailed info. Run the cuprizorb at least 2 weeks past when your copper test shows zero. If you use chemi pure or a high quality carbon, like rox carbon; put that in now. I also run a poly filter after that, you'll see it will turn blue if there is still copper in the system. You can return your inverts at this point, and all is well. I've done this on 2 systems, one has inverts the other is a full reef. Cupramine seem to be a very good product that can also be completely remove if cuprizorb, carbon, and poly filters are ran long enough afterwards. People kill more fish removing them to inadequate qt tanks and reinfect fish by trying to only treat the ones showing symptoms. Keeping a tank fallow for 90 days can also be challenging and even then fish have been reinfected. This is another choice that is sometimes the best choice.