ParaGuard is the only fish and filter safe aldehyde based (10% by weight) parasite control product available (for parasites on fish). Unlike highly toxic and difficult to use formalin based medications, ParaGuard contains no formaldehyde or methanol and will not alter pH. ParaGuard employs a proprietary, synergistic blend of aldehydes, malachite green, and fish protective polymers that effectively and efficiently eradicates many ectoparasites (e.g. ich, etc.) and external fungal/bacterial/viral lesions (e.g., fin rot). It is particularly useful in hospital and receiving tanks for new fish and whenever new fish are introduced to a community tank. WARNING! Do not eat, drink, or get into eyes! In case of eye exposure, promptly & thoroughly wash eyes with water & seek medical attention. Aquarium Use Only. Keep Away from Children. For ornamental fish only. Not for human consumption. Not to be used in conjunction with animals used for human consumption.