preservation

1) the process of storing organisms in a museum indefinitely by some process that halts decay. Fishes are preserved by immersion in formalin (an aqueous solution of formaldehyde) at concentrations depending on the size (thickness) of the specimen (usually in the 5-10% range). Large specimens may require injection to ensure that the formalin reaches internal tissues. Formalin fixes the proteins, stops enzymatic decay and kills bacteria. Specimens are later transferred to an ethanol solution (70-80%) which is non-carcinogenic and easier to work with.