ZIRC Health Services Sample/Specimen Preparation

Bacteriology and Necropsy Exam
Fish intended for bacteriology and/or necropsy exam should be shipped alive (see Shipping Instructions). Shipping containers for shipping live fish are available upon request. Bacteriology samples can also be taken from frozen specimens if necessary.
Histopathology Sample Preparation
For optimum results, fish must be alive and euthanatized just prior to fixation. Autolysis occurs rapidly once a fish dies. This makes fish that are found dead poor specimens for histopathology. Do not freeze fish intended for histopathology. Fish should be fixed prior to shipment using the protocol specified below. Please prepare specimens as follows:
- Fixation Protocol for Histopathology Specimens
- Prepare Dietrich's Fixative (100 ml) as follows. Store fixative at room temperature.
  - 30 ml Ethanol (95%)
  - 10 ml Formalin (Formaldehyde 37% solution, histological grade, contains 10-15% methanol, Sigma # F1635)
  - 2 ml Glacial Acetic Acid
  - 58 ml Distilled Water
- Euthanatize fish with an overdose of MS-222 (tricaine methane sulfonate).
- Carefully slit open the body cavity along the belly, trying not to disrupt internal organs.
- Use 10-15 ml of fixative per 1-2 fish in a sealable container. The volume of fixative should be at least 10 times the volume of the specimen.
- Store and ship fixed fish in Dietrich's fixative. Fish can be stored for several weeks in Dietrich's fixative.