We have developed a percutaneous infection model with zebrafish (Dani rerio) and analyzed skin bacterial floras during the infection. The fish were given the combination of the unpleasant situations such as temperature shift and /or skin injury before being exposed to a fish pathogen, Yersinia ruckeri. The composition of skin bacterial floras on the zebrafish during infection experiments was analyzed by sequencing of amplified 16S rDNA.