Fish Diseases and Management

Samples for histology

Samples for histology must be taken as soon as possible after death of the fish and fixed immediately, preferably in neutral buffered formalin.

The organs sampled depend on the nature of the problem however, here all the major organs can be sampled e.g. gill, skin including muscle around lateral line, heart, liver, pancreas/ gut, spleen and kidney. The samples should be sufficiently small to allow the fixative to penetrate rapidly through the tissue. Therefore the dimensions of the tissue removed should be less than 7.5 mm. The tissues should be placed in at least 10 times their volume of fixative i.e. one part tissue to ten parts fixative. The tissue can be kept in formalin for prolonged periods but they should be stored in such a way as to avoid any portion of the tissues remaining out of the fixative. (Histological analysis is dealt separately)