Recurring Ulcers in 11,000-Gal Pond: Bacterial Infection from Slime Coat Failure

11,000-gal pond, mixed fish. Ulcers last year, treated for “fluke” (green water-ticks) per dealer, didn’t work. Cold winter, filter ran. Now sores again. Owner asks next step.

Dealer Misdiagnosis

Flukes are visible (green, tick-like). If dealer saw them, they’d be obvious. Recurring ulcers = bacterial infection (Aeromonas/Pseudomonas) secondary to slime coat damage.

Root Causes of Slime Coat Loss

• pH swings (high/low or daily fluctuations).
• Low KH → unstable pH.
• High GH → impairs slime regeneration.
• High ammonia/nitrate.

Treatment Protocol

1. Correct chemistry (test all parameters).
2. Fuba Fix or similar antibacterial: dose per label, repeat per schedule.
3. When slime coat returns (fish look glossy), monitor for parasites.
4. Quarantine all new fish—stores harbor bacteria.

Fire the dealer. Fluke is easy to ID; ulcers need water-quality detective work.