Fish Quarantine: Current Practices in Public Zoos and Aquaria
IAAAM 2009
Catherine A. Hadfield; Leigh A. Clayton
National Aquarium in Baltimore, Baltimore, MD, USA


Several common infectious diseases of fish can cause acute mortalities, e.g., Ichthyophthirius, Cryptocaryon, and Amyloodinium. Other infectious diseases are often associated with chronic morbidity and loss of aesthetics, e.g., Neobenedinia, Lernaea, and lymphocystis. If these diseases are introduced into large exhibits, diagnostic and treatment options can be severely limited by accessibility, species composition, system volume and life-support, and the need to maintain an aesthetic exhibit.

Quarantine helps to decrease the risk of introducing infectious diseases into established exhibits by allowing monitoring, diagnostics, and treatments while fish are isolated from collection animals. Fish quarantine recommendations have been published elsewhere; this paper will review current practices within public zoos and aquaria.2-6

At the time of abstract submission, 33 institutions have contributed information on their fish quarantine protocols using questionnaires; 30 of these have predominantly closed (or re-circulating) systems.

More than 50% of the institutions surveyed have separate quarantine protocols for freshwater teleosts, saltwater teleosts, and elasmobranchs; some have separate protocols for syngnathids or for cold-water and tropical species. All tailor their actual quarantine plans to accommodate known or suspected species' sensitivities.

Approximately 80% of institutions aim for a minimum quarantine period of 30 days, as recommended by the AZA; approximately 10% use longer quarantine periods.1 Several facilities shorten the quarantine period for logistic reasons in specific cases, especially for elasmobranchs. Approximately 50% of institutions have a designated fish quarantine area, although many of these institutions also quarantine fish in back-up or holding areas. Approximately 25% of facilities have designated fish quarantine staff.

Routine diagnostics on teleosts are carried out by approximately 30% of institutions, and these usually consist of exams, skin scrapes, and gill biopsies from < 10% of most groups. Routine diagnostics on elasmobranchs are carried out by just over 50% of the facilities and can include exams, skin scrapes, gill biopsies, morphometrics, diagnostic imaging, bloodwork, fecal samples, and coelomic aspirates. All facilities carry out necropsies on animals that die in quarantine.

More than 80% of institutions report using routine hypo- and hyper-salinity treatments. These include freshwater or saltwater dips at the start and/or end of quarantine, and 3-5 ppt long-term baths for many freshwater fish. Salinity changes are the mainstay of parasite control for aquaria with predominantly flow-through systems.

More than 60% of institutions with closed systems use copper sulfate baths for marine teleosts at 0.15-0.25 mg/L Cu2+ for 14-30 days. Alternatives to copper therapy include salinity changes, formalin, chloroquine, or either an extended quarantine or further diagnostics. Over 50% of institutions with closed systems use formalin baths for teleosts, with doses ranging from 12.5-25 mg/L for long-term baths, to 125-250 mg/L for 30-60 min baths. Organophosphate use is rare and only occurs in response to specific parasites that cannot be treated with other medications.

Medicated feeds containing fenbendazole and praziquantel are often used routinely in teleosts; doses vary widely. Praziquantel is also often used as a bath for teleosts and elasmobranchs, with doses ranging from 2 mg/L long-term baths, to 10 mg/L 3-hr baths. Antibiotics are not used routinely by most institutions, although other antibacterials are used. Two institutions report routine use of vibriosis vaccines in syngnathids.


The following institutions all very generously provided information on their fish quarantine procedures:

 Adventure Aquarium, NJ

 Alaska Sealife Center, AL

 Aquarium of Niagara, NY

 Audubon Aquarium of the Americas, LA

 Calvert Marine Museum, MD

 Chicago Zoological Society; Brookfield Zoo, IL

 Cincinnati Zoo and Botanical Garden, OH

 Columbus Zoo and Aquarium, OH

 Dallas Aquarium; Fair Park, TX

 Florida Aquarium, FL

 Indianapolis Zoological Society, IN

 John G. Shedd Aquarium, IL

 Mote Marine Laboratory and Aquarium, FL

 Mystic Aquarium, CT

 National Aquarium Institute, MD/DC

 New England Aquarium, MA

 Newport Aquarium, KY

 North Carolina Aquaria; Fort Fisher, Pine Knoll Shores, Roanoke Island, NC

 Oklahoma City Zoological Park, OK

 Omaha's Henry Doorly Zoo, NE

 Oregon Zoo, OR

 The Seas with Nemo and Friends at Walt Disney World, FL

 SeaWorld San Antonio, TX

 SeaWorld San Diego, CA

 Smithsonian National Zoological Park, DC

 South Carolina Aquarium, SC

 Texas State Aquarium, TX

 World Aquarium, MO

 Bermuda Aquarium, Bermuda

 Bristol Zoo Gardens, England

 Underwater World, Singapore

 Vancouver Aquarium Marine Science Centre, Canada

 Zoological Society of London, England



1.  Association of Zoos and Aquariums. 2009. The accreditation standards and related policies.

2.  Harms C.A. 2003. Fish. In M.E. Fowler and R.E. Miller (eds.), Zoo and Wild Animal Medicine: Current Therapy, 5th ed. W.B. Saunders, Philadelphia, PA; Pp. 2-20.

3.  Harms C.A. 1993. Quarantine procedures for fish aquaria. Annual Proceedings of the American Association of Zoo Veterinarians; Pp. 63-66.

4.  Lewbart G.A. 1993. Preventative medicine for freshwater and marine aquarium fishes. Annual Proceedings of the American Association of Zoo Veterinarians; Pp. 67-72.

5.  Stoskopf M.K. 1993. Fish Medicine. W.B. Saunders, Philadelphia, PA.

6.  Whitaker B.R. 1999. Preventative medicine programs for fish. In: M.E. Fowler and R.E. Miller (eds.), Zoo and Wild Animal Medicine: Current Therapy, 4th ed. W.B. Saunders, Philadelphia, PA; Pp. 163-181.


Speaker Information
(click the speaker's name to view other papers and abstracts submitted by this speaker)

Catherine A. Hadfield
National Aquarium in Baltimore
Baltimore, MD, USA

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