Formulation evidence record
Seachem ParaGuard
External parasite and fungal treatment · US formulation
Shrimp
Amano, cherry, crystal and other freshwater shrimp.
Snails
Nerite, mystery, ramshorn and other aquarium snails.
Live plants
Rooted and floating live aquarium plants.
Scaleless fish
Loaches, corydoras, plecos, eels and other scaleless species.
Marine invertebrates
Corals, anemones, starfish and marine crustaceans.
Not addressed by the manufacturer for: biological filter. No statement was found, so no verdict is given — that is not a clearance.
Why FishyMag says this
The manufacturer's own wording, quoted rather than paraphrased, so you can judge it yourself.
Shrimp
CautionSeachem explicitly declines to certify this as invertebrate safe, and says so in unusually candid terms. They suggest keepers who proceed start at a quarter to half dose and watch for reactions — which is guidance for accepting a risk, not a safety clearance.
Contains aldehydes, with a source-linked caution associated with this group. This raises a flag—it is not the basis of the verdict above.
“We do not sell or market ParaGuard™ as invert safe because it would be impossible to test it with every available invert under every potential water parameter.”
manufacturer faq · seachem.com · checked August 16, 2026
Snails
CautionCovered by the same statement as shrimp — Seachem does not market ParaGuard as invertebrate safe, and does not single snails out as an exception.
Contains aldehydes, with a source-linked caution associated with this group. This raises a flag—it is not the basis of the verdict above.
“We do not sell or market ParaGuard™ as invert safe because it would be impossible to test it with every available invert under every potential water parameter.”
manufacturer faq · seachem.com · checked August 16, 2026
Live plants
CautionSeachem describes it as generally safe in planted aquaria, but frames this as their experience rather than a tested guarantee. That is weaker than a label claim, so it is recorded as caution rather than compatible.
“generally safe to use in planted aquaria”
manufacturer faq · seachem.com · checked August 16, 2026
Scaleless fish
CautionPermitted, with an explicit instruction to start low. Seachem says scaleless species can be more sensitive and recommends beginning at a quarter to half dose before building up.
Contains malachite green, with a source-linked caution associated with this group. This raises a flag—it is not the basis of the verdict above.
“You can use any of our medications with scaleless fish, but as they can be more sensitive, we would recommend that you begin with a 1/4 to 1/2 dose first and slowly build to the recommended dosage.”
manufacturer faq · seachem.com · checked August 16, 2026
Marine invertebrates
CautionThe same non-certification applies. Seachem will not describe the product as invertebrate safe for any invertebrate group.
Contains aldehydes, with a source-linked caution associated with this group. This raises a flag—it is not the basis of the verdict above.
“We do not sell or market ParaGuard™ as invert safe because it would be impossible to test it with every available invert under every potential water parameter.”
manufacturer faq · seachem.com · checked August 16, 2026
Product details
- Manufacturer states it treats
- External parasites, Fungal infections, Bacterial and viral lesions
- Chemical filtration
- Remove chemical filtration during treatment
- Ingredients as stated
- A proprietary, synergistic blend of aldehydes, malachite green and fish protective polymers (10% aldehydes by weight).
- Active ingredients
- AldehydesMalachite green
manufacturer page · seachem.com · checked August 16, 2026
Record last checked August 16, 2026 · confidence high
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External parasite and fungal treatment · US formulation
Permitted, but with conditions.
The manufacturer stops short of clearing this for something in your tank. Read the detail below before you dose.
- ShrimpCaution
Seachem explicitly declines to certify this as invertebrate safe, and says so in unusually candid terms. They suggest keepers who proceed start at a quarter to half dose and watch for reactions — which is guidance for accepting a risk, not a safety clearance.
- SnailsCaution
Covered by the same statement as shrimp — Seachem does not market ParaGuard as invertebrate safe, and does not single snails out as an exception.
- Live plantsCaution
Seachem describes it as generally safe in planted aquaria, but frames this as their experience rather than a tested guarantee. That is weaker than a label claim, so it is recorded as caution rather than compatible.
See the manufacturer’s exact wording and sources for Seachem ParaGuard →
No evidence found means no manufacturer statement was found — not that the product is safe. FishyMag does not diagnose disease or recommend treatments.
Other treatments
Next steps
FishyMag reports what manufacturers say, quoted and linked. It does not diagnose illness or recommend a treatment, and it never infers that a product is safe from the absence of a warning — where no statement exists, it says so.
Formulations change. Always read the label on the bottle in your hand, and contact the manufacturer if your tank contains anything valuable or unusual.