Zeovit Flatworm Stop will help reduce parasitic flatworms on Acropora and SPS corals while strengthening all other types of corals. It works by making Acropora tissue unpalatable to Acro-Eating Flatworms, slowly starving them. As a long-term treatment, there is no danger of sudden flatworm die-off and the associated spike in waterborne toxins. Flatworm Stop will also improve growth and vigor and can be used on a continual basis.