Formulation evidence record
Fritz Aquatics Expel-P
Internal nematode 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.
Marine invertebrates
Corals, anemones, starfish and marine crustaceans.
Biological filter
The nitrifying bacteria in your filter media.
Not addressed by the manufacturer for: scaleless fish. 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
Manufacturer states compatibleFritz states Expel-P is safe for plants and invertebrates and does not harm uninfected fish. This is one of the clearer invertebrate clearances in the database.
“It does not harm the bio-filter, plants, other invertebrates or uninfected fish”
manufacturer page · fritzaquatics.com · checked August 16, 2026
Snails
CautionFritz clears invertebrates generally, then carves snails out: some species may be temporarily affected. That qualifier is the reason this is not recorded as compatible — a blanket invertebrate claim does not override the manufacturer’s own exception.
“Some snail species may be temporarily affected”
manufacturer page · fritzaquatics.com · checked August 16, 2026
Live plants
Manufacturer states compatibleFritz states the product does not harm plants.
“It does not harm the bio-filter, plants, other invertebrates or uninfected fish”
manufacturer page · fritzaquatics.com · checked August 16, 2026
Marine invertebrates
CautionCleared broadly, but Fritz notes tube worms and feather dusters may be negatively affected — worth knowing before dosing a reef system.
“Tube Worms and Feather Dusters may be negatively affected.”
manufacturer page · fritzaquatics.com · checked August 16, 2026
Biological filter
Sources disagreeFritz says it does not harm the bio-filter in one place and warns that treatment may inhibit nitrifying bacteria in another. Monitor ammonia and nitrite through the course regardless of which reading you favour.
Contains levamisole hcl, with a source-linked caution associated with this group. This raises a flag—it is not the basis of the verdict above.
“It does not harm the bio-filter, plants, other invertebrates or uninfected fish.”
manufacturer page · fritzaquatics.com · checked August 16, 2026
“Treatment may inhibit nitrifying bacteria. Monitor ammonia and nitrite levels during treatment.”
manufacturer page · fritzaquatics.com · checked August 16, 2026
Check the evidence boundary
What this record can—and cannot—answer
US formulation · label revision: not recorded · version: not recorded.
Match the label and concentration on your bottle before using a dose ratio.
Scaleless fish
Missing evidence is not a compatibility finding.
No specific interaction warning is recorded here. This is not a complete interaction review or permission to combine treatments.
Formulation record checked August 16, 2026. Source dates can differ within the record. A dated check is not a guarantee that the label has stayed unchanged.
Product details
- Manufacturer states it treats
- Camallanus worms, Internal nematodes, Detritus worms
- Chemical filtration
- Not stated by the manufacturer
- Ingredients as stated
- Levamisole HCl.
- Active ingredients
- Levamisole HCl
manufacturer page · fritzaquatics.com · checked August 16, 2026
Record last checked August 16, 2026 · confidence high
Check against your tank
Change what is in your tank to see how the answer moves.
The biological filter is included in every non-empty tank check, alongside your selected groups.
Internal nematode treatment · US formulation
Sources disagree about your tank.
We found credible sources that contradict each other. Both are shown below so you can judge — when in doubt, follow the manufacturer.
This answers for the assumed selection above, not a tank you have described. Adjust it if it is not yours.
- ShrimpManufacturer states compatible
Fritz states Expel-P is safe for plants and invertebrates and does not harm uninfected fish. This is one of the clearer invertebrate clearances in the database.
- SnailsCaution
Fritz clears invertebrates generally, then carves snails out: some species may be temporarily affected. That qualifier is the reason this is not recorded as compatible — a blanket invertebrate claim does not override the manufacturer’s own exception.
- Live plantsManufacturer states compatible
Fritz states the product does not harm plants.
- Biological filterSources disagree
Fritz says it does not harm the bio-filter in one place and warns that treatment may inhibit nitrifying bacteria in another. Monitor ammonia and nitrite through the course regardless of which reading you favour.
See the manufacturer’s exact wording and sources for Fritz Aquatics Expel-P →
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.