I've worked on approx 200 projects, never experienced a kill event due to polymer [except one case treating a 2' max depth pond]. I've treated all 7 of my ponds with existing fisheries and have only found a handful of YOY BG and FHM morts following polymer treatment. Check stomach contents of some morts - will address the polymer question. Any FHM morts or just BG?
How's the pond level holding?