quarantine all new fish in a separate aquarium with copper / cupramine by seachem. corals and inverts like snails and shrimp cannot be placed in copper. Copper kills them instantly! Although ich does not affect inverts, it can hitch a ride on them and enter your tank. If you aren’t sure if there are salt crystals on their body, you will really be able to see them under the blue lighting of your LED lights. I am using my last tank, 75 gallon, as the quarantine tank. The 28 gallon was too small for the Tangs I have. I bought this canister filter for filtration on this new quarantine tank. I love this thing. You must clean canister filters once a week to remove all the fish waste and uneaten food. If not, these toxins will pollute your water. I have added 2 more LARGE pvc pipe as well, for them to hide in and swim around. Ich and Marine Velvet are DEADLY! They will wipe your tank out within hours if you don’t act fast. Fish will not build up an immunity to a flesh eating parasite. You must kill the parasite. Once you do, you will never have ich issues unless you accidentally allow it in your aquarium. You kill the parasite by starving it, removing fish, the food source, for 6 weeks minimum, from your aquarium. This is the only cure. Again, do NOT use copper with any inverts such as shrimp, star fish, snails, or corals.