The digestive system of teleost fish has a high structural diversity based on modes, living environments and diets. This study aims to qualitatively and quantitatively determine the diet of Scorpaena notata and describe the adaptation of the histological structure of the digestive tract with enzymatic secretion compared to the nature of ingested prey. This study was performed using three approaches: histology of different parts of the digestive tract, stomach contents analysis, and enzymatic assay. A total of 350 small red scorpion fish individuals were collected from small landings in the region of Algiers. The composition of the diet shows that S. notata is a macrophagous species with a large alimentary spectrum of prey. The diet consists of decapoda brachyura, other crustaceans and fishes. A digestive enzymology test reveals that the activity of chitinolytic enzymes is particularly high in the scorpion fish stomach in general; the major preys are known by their carapace rich on chitin. This result was obtained by the extraction of crude chitinases from the offal of these fish. It was confirmed by the histological structure of the lamina propria of the stomach mucosa showing a dense glandular exocrine serous form, when the intestinal structure are much less dense at the mucosa.