Appearance of surviving fishes (asymptomatic) of negative control (a), positive control challenged with P. fluorescens (b), treated by Sphingomonas sp. AsCh-P3 (c-e) and Bacillus aerius AsCh-A7 (f-h) representing for different experimental groups G1a, G1b, G1c, G2a, G2b, G2c, respectively.