FISH HEALTH MANAGEMENT 341 



oxygen usually provide room for expansion. A general precaution is to use 

 a double bag system, one bag filled and sealed within another. It is best to 

 ship a minimum number of specimens. Sick fish and coldwater fish, such as 

 trout, require greater volumes of water than healthy or warmwater fish. 

 Twenty volumes of water for each volume of fish usually will be adequate 

 for healthy fish, but greater volumes should be provided for sick fish. Dur- 

 ing extreme hot or cold weather, insulated containers may be required. 

 Expanded polystyrene picnic hampers provide good insulation but are rela- 

 tively fragile and require protection against damage. They should be 

 packed, therefore, in a protective corrugated cardboard box or other con- 

 tainer. Coldwater fish usually ship better if ice is provided. The ice should 

 be packed in double plastic bags so that it will not leak when it melts. 



Shipping Preserved Specimens 



Preservatives typically are corrosive and odorous. Containers should be un- 

 breakable and absorbent material should be provided in the event leakage 

 does occurs. A good procedure is to fix the fish in a proper fixative for a 

 day or two, then place the preserved fish, with a very small volume of fixa- 

 tive, in a plastic bag. The sealed bag should be placed within a second 

 plastic bag, which also should be sealed. This durable package has minimal 

 weight. Select representative specimens. Examine them carefully to supply 

 data in the order given in the Diagnostic Summary Information form. 

 Bouin's solution is a preferred fixative. Its recipe is: picric acid 

 (dangerous), 17.2 grams; distilled water, 1,430 milliliters; formalin, 475 mil- 

 liliters; glacial acetic acid, 95 milliliters. NOTE: picric acid explodes when 

 rapidly heated. Handle accordingly. Weigh picric acid and place crystals in 

 a pyrex container large enough to hold 2 liters (2,000 milliliters) and add 

 distilled water. Heat on a stove. Stir occasionally until all crystals are dis- 

 solved. Do not boil the solution. When crystals have dissolved, remove the 

 solution from the stove and cool it completely. Add the formalin and gla- 

 cial acetic acid to the cooled solution. Stir briefly and pour the mixture 

 into a jar. This solution will keep well, but should be protected from 

 freezing. 



Volume of the fixative should be at least five to ten times that of the 

 fish or tissue. (Thus, put only one 6- inch fish in a pint of fixative.) Fish 

 and tissues should be left in the fixative for at least 24 hours, and then the 

 fixing solution replaced with 65% ethyl alcohol. However, if alcohol is not 

 available, retain the specimens in Bouin's fluid. 



To facilitate fixation, fish, regardless of size, should be slit down the ab- 

 domen from the anus to the gills. The air bladder should be pulled out and 

 broken to permit fixation of the kidney. The kidney of 6-inch or larger fish 

 should be split along its entire length. The intestines and other organs 



