The Seachem ParaGuard is the only fish and filter safe aldehyde based (10% by weight) parasite control product available (for parasites on fish). 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).