Formulation evidence record
Seachem PolyGuard
Broad-spectrum bacterial, fungal and parasitic 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.
Biological filter
The nitrifying bacteria in your filter media.
Why FishyMag says this
The manufacturer's own wording, quoted rather than paraphrased, so you can judge it yourself.
Shrimp
Manufacturer advises againstSeachem’s dosing directions for this product instruct removing all invertebrates before treatment. The identical sentence appears across their medication range, so it reads as a blanket precaution rather than testing specific to this formulation.
“Remove all invertebrates - these are extremely sensitive to medication.”
manufacturer page · seachem.com · checked August 16, 2026
Snails
Manufacturer advises againstSnails fall under the same instruction — Seachem tells keepers to remove all invertebrates before treatment and does not single snails out as an exception.
“Remove all invertebrates - these are extremely sensitive to medication.”
manufacturer page · seachem.com · checked August 16, 2026
Live plants
No evidence foundNo statement from the manufacturer was found for this group. Treat it as unconfirmed and check before dosing.
No manufacturer statement was found for this group. That is not the same as a clearance — treat it as unconfirmed and ask the manufacturer before dosing.
Scaleless fish
No evidence foundNo statement from the manufacturer was found for this group. Treat it as unconfirmed and check before dosing.
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.
No manufacturer statement was found for this group. That is not the same as a clearance — treat it as unconfirmed and ask the manufacturer before dosing.
Marine invertebrates
No evidence foundNo statement from the manufacturer was found for this group. Treat it as unconfirmed and check before dosing.
No manufacturer statement was found for this group. That is not the same as a clearance — treat it as unconfirmed and ask the manufacturer before dosing.
Biological filter
No evidence foundNo statement from the manufacturer was found for this group. Treat it as unconfirmed and check before dosing.
No manufacturer statement was found for this group. That is not the same as a clearance — treat it as unconfirmed and ask the manufacturer before dosing.
Product details
- Manufacturer states it treats
- Fin rot, Hemorrhagic septicemia, Ich (white spot), Mouth rot, Fungus
- Chemical filtration
- Remove chemical filtration during treatment
- Ingredients as stated
- Sulfathiazole (36%), malachite green (1.9%), nitrofurantoin (0.14%), nitrofural (0.14%), quinacrine dihydrochloride (0.27%).
- Active ingredients
- Malachite green
manufacturer page · seachem.com · checked August 16, 2026
Record last checked August 16, 2026 · confidence medium
Check against your tank
Change what is in your tank to see how the answer moves.
Broad-spectrum bacterial, fungal and parasitic treatment · US formulation
The manufacturer advises against using this with your tank.
At least one thing you listed is named in a warning. Move that livestock to another tank, or choose a different treatment.
- ShrimpManufacturer advises against
Seachem’s dosing directions for this product instruct removing all invertebrates before treatment. The identical sentence appears across their medication range, so it reads as a blanket precaution rather than testing specific to this formulation.
- SnailsManufacturer advises against
Snails fall under the same instruction — Seachem tells keepers to remove all invertebrates before treatment and does not single snails out as an exception.
- Live plantsNo evidence found
No statement from the manufacturer was found for this group. Treat it as unconfirmed and check before dosing.
See the manufacturer’s exact wording and sources for Seachem PolyGuard →
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.