In Experiment 1, fingerlingswere stocked into 18-L aquaria at a density
of 10 fish per aquarium. Aquaria contained 10 L of aerated water;
starting on the second day, 50% of the water was exchanged daily.
Five aquariawere used to assess 4-d survival for each of the twowaters:
one negative control and four replicate aquaria. Fish in one replicate
tank of each water were used to measure adhesion of bacteria to gills
24 h after challenge. Water temperatures averaged 19.1 °C and
dissolved oxygen averaged 8.7 mg/L throughout the experiment. Total ammonia-nitrogen (TAN) concentrations averaged 2.1 mg/L; tanks
with highermortalities had higher TAN concentrations. Fishwere maintained
on a 12 h light:12 h dark photoperiod under fluorescent lights