New Life Spectrum Ick Shield Pellets is a medicated food designed to combat aquarium ectoparasites.Allows for treating fish without dosing the water, so it's safer for reef tanks.Kills the most damaging feeding stage of the parasite (Trophont) while in the gills and below the skin.Ick Shield fed to newly acquired fish, even fish not showing symptoms in a quarantine tank for the full treatment cycle (21 days) is recommended for prevention and to reduce the likelihood of outbreaks in your reef.