Zonula occludens toxin (Zot) is a conserved protein in filamentous vibriophages and has been reported as a putative toxin in . Recently, widespread distribution of encoding prophages was found among marine species, including environmental isolates . However, little is known about the dynamics of these prophages beyond . In this study, we characterized and quantified the encoding filamentous phage VAIϕ, spontaneously induced from the fish pathogen . VAIϕ contained 6117 bp encoding 11 ORFs, including ORF8, exhibiting 27% -73% amino acid identity to Zot-like proteins . A qPCR method revealed an average of four VAIϕ genomes per host genome during host exponential growth phase, and PCR demonstrated dissemination of induced VAIϕ to other strains through re-integration in non-lysogens . VAIϕ integrated into both chromosomes of by recombination, causing changes in a putative ORF in the phage genome . Phylogenetic analysis of the elements revealed mosaic genome structures related to mainly . Altogether, this study contributes to the understanding of infection dynamics and mobilization of -like genes beyond human pathogenic vibrios, and discusses their potential role in the evolution of the fish pathogen.