In Experiment 1, fish were exposed to a bacterial challenge of F. columnare in aquariawith either SNARC or WARU
water. Fish mortality at 4 d was 100% for fish in SNARCwater, while no fish died in WARU water. Bacterial adhesion
to gill surfaces also differed dramatically in the two waters and was approximately 1900-times higher for
fish challenged in SNARC water (more than 800,000 bacterial CFUs/ng extracted DNA) than for fish challenged
in WARU water (fewer than 450 CFUs/ng).