ParaGuard is the only fish and filter protected aldehyde based (10% by weight) parasite keep an eye on product to be had. Unlike highly toxic and difficult to use formalin based medications, ParaGuard comprises no formaldehyde or methanol and won’t alter pH. ParaGuard employs a proprietary, synergistic blend of aldehydes, malachite green, and fish protective polymers that effectively and efficiently eradicates many ectoparasites on fish (e.g. ich, and the like.) and external fungal/bacterial/viral lesions (e.g., fin rot). It is particularly useful in hospital and receiving tanks for new fish and on every occasion new fish are introduced to a community tank. To be used in freshwater or marine. ParaGuard is really helpful for the remedy of certain diseases in marine and freshwater fish only. It IS NOT really helpful for treating any style aquarium containing invertebrates, corals, crustaceans, or elasmobranchs (sharks and rays).