Vibrio harveyi

  • Coral and fish pathogen

Overview

Vibrio harveyi is a Gram-negative marine bacterium recognized as one of the most significant pathogens in marine aquaculture worldwide. This bioluminescent pathogen causes vibriosis and mass mortalities across a diverse range of hosts including fish, shrimp, mollusks, and other marine invertebrates. Known for its ability to form biofilms and utilize quorum sensing mechanisms, V. harveyi has emerged as a major economic threat to the aquaculture industry, with outbreaks becoming increasingly frequent as ocean temperatures rise.

Affected species (hosts)

Primary Marine Fish Hosts:

  • Gilthead seabream (Sparus aurata) – principal cause of vibriosis
  • European seabass (Dicentrarchus labrax) – high mortality rates
  • Barramundi (Lates calcarifer) – hypervirulent strains cause 100% mortality
  • Large yellow croaker (Larimichthys crocea) – increasing disease prevalence
  • Yellowfin seabream – virulent infections
  • Hybrid grouper – coinfections increase mortality
  • American eel (Anguilla rostrata) – high virulence even in freshwater

Corals and other Cnidarians:

  • Stony corals including Pocillopora and  Montastraea
  • The nuisance anemone Aiptasia

Crustacean and Mollusk Hosts:

  • Penaeus monodon shrimp – high larval mortality
  • Various marine shrimp species
  • Mussels and oysters – virulence genes present
  • Abalone and other gastropods

Antibiotic Resistance and Treatment Challenges

Multidrug Resistance. One of the most concerning aspects of V. harveyi infections is the widespread development of antibiotic resistance. Many strains show multidrug resistance patterns, though some remain sensitive to florfenicol, norfloxacin, and ciprofloxacin.

Effective Antibiotics: When antibiotic treatment is necessary, chloramphenicol, ciprofloxacin, oxytetracycline, and florfenicol have shown efficacy against certain strains. However, resistance patterns vary by geographic region and should be tested before treatment.

Alternative Control Methods: Due to rising antibiotic resistance, alternative treatments are being developed including probiotics, immunostimulants, vaccines, bacteriophage therapy, and electrolyzed water disinfection. Microalgae extracts have also shown promise in inhibiting bacterial growth.

Environmental Factors: Warmer water temperatures increase V. harveyi virulence and outbreak frequency. Climate change and intensive aquaculture practices are contributing to more severe and frequent disease outbreaks worldwide.

Biofilm Formation: V. harveyi’s ability to form biofilms makes infections particularly difficult to treat and contributes to persistence in aquaculture systems. Some probiotic bacteria like Bacillus subtilis can inhibit biofilm formation.

Management and Prevention Strategies

Prevention. Quarantine new fish and corals for 2-4 weeks minimum, with separate filtration for quarantine systems.  

Temperature Management. Monitor and control water temperatures, as V. harveyi virulence increases significantly with elevated temperatures. This is particularly important as climate change continues to warm ocean waters.

Testing. Test new arrivals in the QT to make sure they’re pathogen-free before introducing them to your display. 

Beware of antibiotic resistance: Antibiotic resistance is widespread in this group. Avoid antibiotic treatments if at all possible.   

If you must use antibiotics: Most Vibrio species are susceptible to Ciprofloxacin and Oxalinic Acid.

But first see this note about the use of antibiotics in aquariums! 

V. harveyi in reef tanks

Prevalence

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Looking at how common this pathogen is in other tanks can help you gauge whether finding it in your tank is expected or unusual.

Abundance Distribution

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Comparing the levels of this pathogen in your tank with those found in other tanks provides a context for interpreting your test results.

References

Zhang, X., He, X., & Austin, B. (2020). Vibrio harveyi: a serious pathogen of fish and invertebrates in mariculture. Marine Life Science & Technology, 2, 231-245. https://doi.org/10.1007/s42995-020-00037-z

Sullivan, R., Becker, J., Zadoks, R., et al. (2025). Vibrio harveyi plasmids as drivers of virulence in barramundi (Lates calcarifer). PLOS One, 20. https://doi.org/10.1371/journal.pone.0319450

Triga, A., Smyrli, M., & Katharios, P. (2023). Pathogenic and Opportunistic Vibrio spp. Associated with Vibriosis Incidences in the Greek Aquaculture: The Role of Vibrio harveyi as the Principal Cause of Vibriosis. Microorganisms, 11. https://doi.org/10.3390/microorganisms11051197

Ghosh, S., Kar, P., Chakrabarti, S., et al. (2023). Pathogenicity of Vibrio harveyi and its biocontrol using bacteriophages. Systems Microbiology and Biomanufacturing, 1-19. https://doi.org/10.1007/s43393-023-00178-z

Blasco, A., Ibányez-Payá, P., Fouz, B., et al. (2025). Use of Electrolyzed Water as Disinfection Technology in Aquaculture Systems: Effects on Vibrio harveyi, a Significant Marine Pathogen for Marine Fish and Invertebrates. Applied Sciences. https://doi.org/10.3390/app15052334

Yang, A., Li, W., Tao, Z., et al. (2021). Vibrio harveyi isolated from marine aquaculture species in eastern China and virulence to the large yellow croaker (Larimichthys crocea). Journal of Applied Microbiology, 131. https://doi.org/10.1111/jam.15070

Deng, Y., Xu, L., Chen, H., et al. (2020). Prevalence, virulence genes, and antimicrobial resistance of Vibrio species isolated from diseased marine fish in South China. Scientific Reports, 10. https://doi.org/10.1038/s41598-020-71288-0

Li, S., Zhang, S., Jiang, W., et al. (2024). Enhanced Detection of Vibrio harveyi Using a Dual-Composite DNAzyme-Based Biosensor. Biosensors, 14. https://doi.org/10.3390/bios14110548

Petit, C., Caudal, F., Taupin, L., et al. (2024). Antibiofilm Activity of the Marine Probiotic Bacillus subtilis C3 Against the Aquaculture-Relevant Pathogen Vibrio harveyi. Probiotics and antimicrobial proteins. https://doi.org/10.1007/s12602-024-10229-z

Xu, H., Zeng, Y., Yin, W., et al. (2022). Prevalence of Bacterial Coinfections with Vibrio harveyi in the Industrialized Flow-through Aquaculture Systems in Hainan Province: A Neglected High-Risk Lethal Causative Agent to Hybrid Grouper. International Journal of Molecular Sciences, 23. https://doi.org/10.3390/ijms231911628