Fish Deaths After Rain: Poisoning Suspect, Carbon, Water Change

1-year pond, 8x13x2.5 ft. 6 fish, added 4 new + plants. 3 days: clouded, then murky green. 4 dead in 2 days. pH 7.5. Rain inches. Asks cause, save remaining.

Rain = Chemistry Shock + Possible Toxins

• Runoff: fertilizer, herbicide, pesticide → poison.
• Dilution: pH, hardness swing → stress.
• New fish: no quarantine → disease.

Emergency

1. Large water change (30–50%) + dechlorinator.
2. Activated carbon in filter (1 week, then remove).
3. Test pH 3x/day (dawn, noon, dusk), ammonia, nitrite, oxygen.
4. Add beneficial bacteria.
5. Floaters (hyacinth) yellow? Add potassium (Flora Fin).

Erratic Swimming = Poisoning

Fish trying to beach = acute toxicity. Water change + carbon = best shot.