Ask a pond manager what makes a bacterial outbreak worse and you usually get the same answer. Warm water, heavy organic load, crowded nets. Fair enough. Bacteria grow faster in the heat, so summer feels like the season to worry about. For one species that instinct is simply wrong. Pseudomonas plecoglossicida virulence peaks at around 18 degrees C, far below the 28 degrees C where the bacterium grows fastest. A 2026 review pulled together the experimental work behind that inversion, and the numbers line up well enough that anyone running ayu, grouper, large yellow croaker, rainbow trout or barramundi should rethink when they watch their stock hardest. It is a…