One-way risk signals
Ingredients
These entries exist to raise warnings, not to issue clearances. Knowing a product contains copper tells you a great deal; knowing it doesn’t tells you almost nothing.
Ingredient context · illustrative15 ingredients
Copper
Manufacturer pages for Cupramine and Coppersafe explicitly instruct keepers to remove invertebrates before dosing their copper-based formulations. FishyMag uses those first-party warnings as a one-way risk signal, never as treatment advice.
Source-linked caution for: shrimp, snails, marine invertebrates · 2 treatments in the database
Malachite green
ParaGuard lists malachite green and its manufacturer advises a reduced starting dose for scaleless fish. That formulation-level instruction creates a caution signal for products listing this ingredient; it does not establish that the ingredient alone causes the sensitivity.
Source-linked caution for: scaleless fish · 3 treatments in the database
Aldehydes
ParaGuard lists aldehydes and its manufacturer declines to market that formulation as invertebrate safe. FishyMag carries that formulation-level uncertainty forward as a caution signal, not as a claim that every aldehyde formulation has the same compatibility profile.
Source-linked caution for: shrimp, snails, marine invertebrates · 1 treatment in the database
Metronidazole
An antiprotozoal and antibacterial used against internal parasites, most often paired with praziquantel. It is one of the clearest demonstrations that formulation matters more than chemistry: Fritz ParaCleanse and API General Cure both use it, but only Fritz states the product is invertebrate safe. API simply does not address shrimp or snails at all.
Source-linked caution for: · 3 treatments in the database
Praziquantel
An anthelmintic used against flukes and tapeworms, and one of the few actives that manufacturers do sometimes certify as invertebrate safe. Fritz states both ParaCleanse and PraziCleanse are safe for plants and invertebrates — but that clearance comes from the manufacturer stating it, not from the molecule.
Source-linked caution for: · 2 treatments in the database
Kanamycin
An aminoglycoside antibiotic used against bacterial infections. Seachem instructs keepers to remove all invertebrates before dosing its kanamycin product, describing them as extremely sensitive to medication — a broader caution than the copper-specific warnings elsewhere in the hobby.
Source-linked caution for: shrimp, snails, marine invertebrates · 1 treatment in the database
Neomycin sulfate
An aminoglycoside antibiotic for bacterial infections. Its record is a useful warning about reading a whole product page rather than one line: Seachem describes it as well tolerated by invertebrates in one place and instructs keepers to remove all invertebrates in another. Both statements are on the same page.
Source-linked caution for: shrimp, snails, marine invertebrates · 1 treatment in the database
Nitrofurantoin
An antibacterial used against internal infections. It appears in this database mainly through Seachem Focus, which binds medication to food rather than dosing the water column — an approach the manufacturer specifically frames as a way to keep medication away from delicate plants and invertebrates.
Source-linked caution for: · 1 treatment in the database
Erythromycin
A macrolide antibiotic used against gram-positive bacterial infections and cyanobacteria. Its notable risk in this database is not to livestock but to the filter: Fritz warns that treatment may inhibit nitrifying bacteria, which means an ammonia spike is a realistic side effect of a course.
Source-linked caution for: biological filter · 1 treatment in the database
Levamisole HCl
An anthelmintic used against internal nematodes, and one of the few actives with an explicit invertebrate clearance that still carries carve-outs. Fritz calls Expel-P safe for invertebrates while noting some snail species may be temporarily affected and that tube worms and feather dusters may react — a level of detail most labels never reach.
Source-linked caution for: biological filter · 1 treatment in the database
Sulfathiazole
A sulfonamide antibacterial. It appears here through Seachem SulfaPlex, whose directions carry the same blanket invertebrate warning Seachem prints across its medication line rather than a finding specific to this chemistry.
Source-linked caution for: shrimp, snails, marine invertebrates · 1 treatment in the database
Minocycline
A tetracycline-class antibiotic used against septicemia and internal bacterial infections. Fritz clears it for invertebrates and plants in its published compatibility table, while noting some plant species may yellow temporarily and that biological filtration should be monitored and re-seeded afterwards.
Source-linked caution for: biological filter · 1 treatment in the database
Sodium chlorite
A non-antibiotic oxidising treatment. Notable in this dataset for how specific its compatibility table gets: Fritz clears invertebrates, plants and coral but singles out starfish and related species as not recommended — a carve-out most labels never bother to make.
Source-linked caution for: · 1 treatment in the database
Gentian violet
A dye used against external parasites and fungal infection. Fritz marks it not recommended for snails and other invertebrates, coral and amphibians, and describes plant tolerance as depending on species rather than clearing plants outright.
Source-linked caution for: shrimp, snails, marine invertebrates · 1 treatment in the database
Fluconazole
An antifungal used against stubborn nuisance algae, notably bryopsis. Fritz describes Expel-F as broadly compatible and explicitly safe alongside Coppersafe, Maracyn and Maracyn Two — but warns it affects desirable macroalgae and can make some corals retract temporarily, which matters in a reef display rather than a fish-only tank.
Source-linked caution for: marine invertebrates · 1 treatment in the database
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.