Treat the cause, not a colour
White spots, cloudy skin, frayed fins and lethargy are observations, not complete diagnoses.
Know the system effects
Some treatments reduce oxygen, damage plants or invertebrates, or disrupt beneficial microbes. Fry may be more sensitive than adults.
Measure volume accurately
Decor and substrate reduce water volume. Even a correctly chosen product can be overdosed when tank volume is guessed.
Avoid combining products
Ingredients may overlap or interact. Never mix medications or household chemicals without qualified guidance.
Use professional diagnosis when stakes are high
Repeated mortality, severe lesions, neurological signs or valuable breeding stock warrant aquatic veterinary advice.