Waters differed in two major characteristics: compared to SNARC water, WARU water contained
appreciable dissolved organic matter (DOM) and very low concentrations of dissolved calcium and magnesium.
In Experiment 1, fishwere exposed to a bacterial challenge of F. columnare in aquaria with either SNARC orWARU
water. Fish mortality at 4 d was 100% for fish in SNARCwater, while no fish died in WARU water.