Vet Med Externships
Diagnostic Lab
Health Certificates
Faculty & Staff
The Industry
Photo Gallery
What's New?!
Contact Info
Job Openings


Fish Disease Diagnostic Laboratory

Services Available

Fish with exophthalmia ("popeye")The Fish Disease Diagnostic Laboratory at the UF/IFAS Tropical Aquaculture Laboratory (TAL) offers a wide range of services.  A water chemistry analysis and necropsy (including initial bacterial culture) are the basic services required in most cases.  Lab personnel work with the client to determine if further tests are needed or desired.  Most tests are performed on-site though some procedures, such as histological processing and virology, are conducted by off-site laboratories.  As with any veterinary practice, the Tropical Aquaculture Laboratory adheres to a strict policy of client confidentiality.

Water Chemistry Analysis

Standard Freshwater Analysis Standard Saltwater Analysis
  • pH
  • Total ammonia nitrogen (TAN)
  • Un-ionized ammonia (UIA)
  • Nitrite (NO2)
  • Chloride
  • Total Hardness
  • Total Alkalinity
  • Salinity
  • pH
  • Total ammonia nitrogen (TAN)
  • Nitrite (NO2)
  • Nitrate (NO3)
Water quality kit and spectrophotometer Additional Available Tests
  • Carbon Dioxide
  • Conductivity
  • Hydrogen Peroxide
  • Iron


Live Exam with External Tissue Biopsies

Performing gill biopsyLive exams may be performed on fish which cannot be sacrificed, such as valuable broodstock, large stock enhancement fish, or fish for exportation.  Evaluation includes a gross visual exam and microscopic examination of gills, fin, and skin.  Blood for bacterial cultures may be collected from large fish.  It is important to note that a live exam is relatively narrow in scope and may or may not result in a definitive diagnosis.



Fish gills under microscopeA necropsy is a post-mortem (after death) examination of an animal.  Whenever possible, a minimum of four live, sick fish should be submitted to the laboratory.  Fish are evaluated during a gross visual exam, and gill, fin, and skin samples are taken for microscopic examination while the fish are still alive.  After the fish are euthanized, the brain and posterior kidney of three to four fish are cultured for bacteria.  The spleen, liver, and other tissues may also be cultured in large fish.  Following bacterial cultures, complete gross and microscopic exams of the internal organs are performed.

Bacterial Culture

Bacterial cultureBacterial cultures are performed as a part of the necropsy but may be performed separately if warranted.  Freshwater fish are routinely cultured on tryptic soy agar with 5% sheep's blood (TSA+B).  Marine fish are cultured on TSB+B and marine agar.  Additional agars, such as Lowenstein-Jensen for the culture of Mycobacterium and Ordals for the culture of Columnaris, are also available.


Bacteria Identification

Biolog microbial identification systemIf bacteria is cultured from the tested fish, it is identified in-house using a Biolog MicroLogTM semi-automated microbial identification system.  In some cases, it may be necessary to submit bacteria cultures to an outside laboratory for identification.



Antibiotic Sensitivity

Antibiotic susceptibility plateIf bacteria is cultured from the tested fish, an antibiotic sensitivity test is run to determine which antibiotic(s) will be effective in treating the bacteria.




Health Certificate

Most importing countries require that a USDA-accredited veterinarian at least visually examine all (or a representative sample) of the animals being shipped.  (USDA-accredited veterinarians are private veterinarians who have special training to sign official USDA health certificates.)  Some countries require additional diagnostic tests for specific diseases. The extent of the veterinary inspection depends on the requirements established by the importing country, not the United States.  The veterinarian will usually charge for this service regardless of whether or not the shipment passes inspection.  It is, therefore, in the exporterís best interest to be confident of the good health of the animals before scheduling an inspection.  Plan ahead when scheduling a shipment requiring health certification to ensure that a USDA-accredited veterinarian and, if necessary, a USDA APHIS Veterinary Services area official are available to perform the inspection.  The Tropical Aquaculture Lab has USDA-accredited veterinarians who can perform the necessary inspections for exportation of ornamental fish and aquatic invertebrates by Florida aquaculture producers in the Tampa Bay area.  For more information, please see our Health Certificates page.


Histopathology photomicrographHistology is the study of cells and tissues on a microscopic level.  It allows for a much closer and more detailed evaluation than wet mount biopsies performed during a typical necropsy. In most cases, tissues which have been preserved in a fixative (such as 10% neutral buffered formalin) are embedded in paraffin, sliced into extremely thin sections, mounted onto a slide, deparaffinized, and stained.  Different stains are used to target different structures, conditions, and organisms.  Tissues are preserved at the Tropical Aquaculture Laboratory during necropsy then sent for processing to the Department of Pathology & Laboratory Medicine at the University of South Florida's College of Medicine.  The prepared slides are evaluated at the Tropical Aquaculture Laboratory and may be sent to a pathologist for further evaluation.


Fresh, whole fish or fresh tissues (prepared at the Tropical Aquaculture Laboratory during necropsy) are submitted to The Florida Department of Agriculture & Consumer Services Kissimmee Animal Diagnostic Lab for detection of viruses through electron microscopy, polymerase chain reaction (PCR,) or cell culture.  Samples may also be sent to the University of Florida's Electron Microscopy Core Laboratory in Gainesville or other colleagues as necessary.

Other Tests

Acid fast bacteria benchtop stainOther available tests include Mycobacterium culture, Mycobacterium identification (through an outside laboratory), and acid fast bacteria benchtop stain.  Please contact the Lab if you need assistance with tests not specifically listed.



For Web Site comments or problems, please contact the Webmaster.
Last updated October 02, 2012.
Copyright © 2006 - 2007 University of Florida.  All Rights Reserved.