What factors lead to spoilage of fish flesh?

A difference in the composition of tissues among different species, climate, procurement and holding practices are amongst few of the important factors that lead to spoilage of fish. 

Spoiling fish flesh, which becomes subject to excessive autolysins, may yield a heat-processed product with a pitted or honeycombed texture, although a restricted degree of proteolysis prior to processing, may result in a desirable softening of the texture of the finished product.