Seachem ParaGuard – Broad-Spectrum Parasite, Fungus & Fin-Rot Treatment

One gentle treatment for parasites, fungus, and more.

A sick fish is stressful — and harsh formalin medications can be as dangerous as the disease, especially for scaleless and sensitive species.

Seachem ParaGuard is the only fish- and filter-safe aldehyde-based parasite treatment (no formaldehyde or methanol, won't alter pH). Its synergistic blend of aldehydes, malachite green, and fish-protective polymers clears many external parasites (ich, flukes, velvet) plus fungal, bacterial, and viral lesions like fin rot — ideal for quarantine and new arrivals.

ParaGuard reflects the science-driven approach Seachem has taken since it was founded in 1979 in Madison, Georgia. As a chemistry-led company whose products are developed and manufactured in-house by chemists and backed by research, Seachem engineered ParaGuard to be filter-safe so it won't harm your biological filtration, and easily removed with activated carbon once treatment is complete.

1. Remove invertebrates and chemical filtration.
2. Dose 5 mL (1 capful) per 40 L (10 US gallons), daily as needed.
3. Continue the full course — 2 weeks is typical for quarantine.

Treat with confidence, gently. Add to cart.

Why Seachem ParaGuard

• Fish- and filter-safe with no formaldehyde or methanol: a gentler aldehyde-based formula that treats scaleless and sensitive species other harsh treatments can't.
• Biofilter-friendly: engineered to be filter-safe so it won't crash the beneficial bacteria in your biological filtration during a course of treatment.
• Easily removed with carbon: once treatment is done, activated carbon lifts residual medication from the water.
• Backed by Seachem chemistry: a synergistic blend of aldehydes, malachite green, and fish-protective polymers developed in-house by chemists since 1979.

Best For

Use ParaGuard in freshwater and marine fish-only aquaria to treat external parasites (ich/white spot, velvet, gill and body flukes) and external fungal, bacterial, and viral lesions such as fin rot. It is gentle enough for prophylactic quarantine of new arrivals, and a good choice for medicated dips. It is not recommended for reef aquaria or invertebrates — remove invertebrates before dosing, or use Seachem MetroPlex as an alternative.

What It Treats

External parasites (ich/white spot, velvet, gill & body flukes) and external fungal, bacterial, and viral lesions such as fin rot. Not recommended for reef aquaria — use Seachem MetroPlex as an alternative.

Directions

Dosing: Remove all invertebrates and any chemical filtration. Use 5 mL (1 capful) of ParaGuard per every 40 L (10 US gallons). Repeat this dose daily as required, as long as fish show no stress.

Medicated dip: For 1-hour dips, use 3 mL per 4 L (1 US gallon) in a separate container. Dips may be extended if fish show no evidence of stress.

Quarantine: ParaGuard is gentle enough to use prophylactically. We generally recommend 2 weeks of treatment to clear possible external infections.

Sensitive fish: Eels, loaches, rays, sharks, and others can be medication-sensitive — start with a partial dose and build to full over several days.

Available Sizes

100 mL, 250 mL, 500 mL, 2 L, 4 L

Warning

Do not eat, drink, or get in eyes. In case of eye exposure, promptly and thoroughly wash eyes with water and seek medical attention.

FAQ

Is ParaGuard safe for invertebrates or reef tanks? No. Remove all invertebrates before dosing and do not use it in reef aquaria. For those setups, consider Seachem MetroPlex instead.

How do I remove ParaGuard after treatment? Run activated carbon in your filter once the course is complete to lift residual medication from the water; be sure to remove chemical filtration while actively dosing.

Can I use ParaGuard as a dip? Yes. For 1-hour medicated dips, use 3 mL per 4 L (1 US gallon) in a separate container, and extend only if fish show no signs of stress.