14 Goldfish Dead in 3 Days: New Pond, Algae Blocker Suspect

90-gal pond installed Wed, 12 fish added. Thu bought Algae Blocker. By Sun 4 dead. Replaced 7, 2 hrs later all dead. Conditioner, clarifier, algae blocker in water. Asks cause.

Acute Poisoning: Algae Blocker Overdose/Toxicity

• Many algaecides toxic to fish, especially in new, uncycled ponds.
• Overdose likely—new pond volume miscalculated?
• "Conditioner, clarifier, algae blocker" cocktail = chemical soup.

Emergency Reset

1. 100% water change.
2. Dechlorinator only.
3. Pond salt (0.1%).
4. Let sit 3 days.
5. Test pH.
6. Add 2–3 fish, monitor.

Shade & Aeration

Add floating plants, run pump 24/7. No chemicals until cycled (4–6 weeks).

Lesson: Cycle pond BEFORE fish. No algaecides in new ponds.