White spot disease causes intense itching. White salt-grain spots appear within 2-3 days of flashing onset.
Microscopic flatworms cause skin irritation. Treat with PraziPro 7-day course.
Toxic water burns gills + skin. Test water first; flashing without spots is often water-quality.
Recently introduced fish may rub once or twice as they adjust to new water chemistry.
Test water first - many "behavior" issues are actually water-quality problems. Use the water parameter checker to score your test results, the disease symptom matcher if you observe physical signs, or the general diagnoser to narrow further. Browse the disease database if illness is suspected.
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