Outer membrane vesicles (OMVs) are nano-sized proteoliposomes shed from the cell envelope of all Gram-negative species. OMVs are now recognized as a generalized secretion pathway that provides a means to transfer cargo to other bacterial cells and eukaryotic cells. OMVs play an important role in pathogenesis, delivering virulence factors to the host cells, including toxins, adhesins, and immunomodulatory molecules. Moritella viscosa is a Gram-negative pathogen that causes winter ulcer disease in several marine fish species. Here, we develop a infection model using lumpfish (Cyclopterus lumpus) and evaluate the toxicity and utilization of OMVs as vaccines. We isolated and characterized M. viscosa OMVs isolated from iron-rich and iron-limited growing conditions. OMVs were characterized by transmission electron microscopy and protein indentification. Lumpfish injected intraperitoneally (i.p.) with 107 colony-forming units (CFU) fish-1 of M. viscosa had rapid mortality and clinical signs after 3 days post-infection. M. viscosa OMVs in both conditions showed a spheric shape (39.8–370 nm diameter) that contains small RNA and DNA. The main OMVs proteins have a molecular size of 45, 30 and 20 kDa. OMVs isolated from iron-limited condition harbor an additional protein of approximately 60 kDa which is absent in OMVs isolate from bacteria grown under iron-rich conditions. The protein band of 60 kDa has several protins, including a metal-dependent carboxypeptidase, glucose-6-phosphate isomerase, glucose-6-phosphate isomerase, peptide ABC transporter, extracellular solute-binding protein, oligopeptide transport system, and permease protein B. Current studies are been conducting to characterize M. viscosa OMVs cargo, toxicity, and utility as vaccine candidates.