For information on fish physiology, see Aquarium Fishes. General methods for clinical evaluation of aquacultured species are similar to those used in aquarium fish. However, for more structured surveillance and pathogen testing, more uniform and standard methods may be required. OIE-accepted diagnostic methods for reportable diseases are described in The Manual of Diagnostic Tests for Aquatic Animals (also known as the OIE Aquatic Manual [www.oie.int/international-standard-setting/aquatic-manual/access-online/]). Another good reference with standards for necropsy and diagnostics is The American Fisheries Society Fish Health Section Blue Book (2014 Ed.) Suggested Procedures for the Detection and Identification of Certain Finfish and Shellfish Pathogens (www.afs-fhs.org/bluebook/bluebook-index.php). Depending on the specific goals for testing (disease diagnostics, health certification, surveillance) and on the ultimate recipient of any testing results (eg, another state agency vs another country), one or both provide excellent information on methodology. Most veterinary practitioners will require additional laboratory support for more advanced diagnostics (eg, virology, histopathology, bacteriology). Therefore, it is important that the laboratory is qualified and, for USDA-APHIS relevant documentation, approved by the USDA-APHIS to run specific diagnostic tests for aquaculture species.