Two Sides of One Dosage

Medications as a Hidden Threat

• Methylene Blue

  • Can interfere with metabolic enzymes.
  • May cause kidney stress with repeated use.
  • Hides underlying issues without addressing root causes.

  Chronic or careless use of methylene blue can stain tissues and disrupt liver function.
  It also impacts beneficial nitrifying bacteria, especially in bioactive systems.
  Misuse creates the illusion of treatment — while the real issue remains undiagnosed.

• Formalin

  • Toxic and carcinogenic.
  • Damages gills, kidneys, and liver.
  • Risky in poorly aerated or overstocked systems.

  Formaldehyde is a known mutagen and toxicant.
  It burns skin and gills, stresses fish with liver/kidney pathology, and consumes oxygen.
  Without extra aeration, it can cause suffocation and acute stress.
  Used blindly, it often causes more harm than the parasite itself.

• Malachite Green

  • Banned in many countries due to carcinogenic risk.
  • Toxic to some species, especially catfish and scaleless fish.

  While effective, malachite green accumulates in tissues and is not safe for food fish.
  Overdoses cause severe gill damage and death.
  Even at normal levels, it stresses sensitive fish and can suppress immunity.
  Its use in public aquaria is increasingly questioned.

• FMC (formalin + malachite green + methylene blue)

  • Frequently ineffective when used in short 5–15 minute dips.
  • Parasites often survive, while fish are weakened.
  • Can create false confidence — “something was done” — but no true cure.
  • Formalin and malachite together increase toxicity, especially in stressed fish.
  • Methylene blue harms biofilters — water degrades fast in closed systems.
  • Lacks proper diagnostics, context, or outcome tracking.

  FMC was once the “go-to” blend. Now, it’s often used as a ritual — with little consideration for water quality, fish health, or actual results.

  If parasites survive and the fish becomes weaker — that’s not medicine, it’s a mistake.

• Antibiotics

  • Promote resistance (Aeromonas, Pseudomonas, etc.).
  • Kill gut microbiota.
  • Leave residues that affect the whole aquarium system.

  Without lab diagnostics (cultures, antibiograms), antibiotics are often useless or harmful.
  They destroy healthy bacteria, trigger dysbiosis, and create resistant strains.
  Surviving pathogens come back stronger.
  Long-term, residual antibiotics destabilize closed systems and reduce resilience.

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Why do these outdated practices persist?

Because no proper treatment records are kept.
No microscope photos, no dosage logs, no post-treatment analysis — no way to tell if something helped or hurt.

To move past ritual and toward results, aquarists and institutions need proper treatment logs and data systems — with diagnostics, follow-ups, and outcome-based decisions.

Only then can we separate science from superstition.