Anabantidae is a large and diverse group of fish cultured both under aquaculture conditions and as a hobby. These fish share a common structural feature in the form of an additional respiratory organ. Despite the enormous availability of these fish worldwide, little is known about their feeding preferences in husbandry and their influence on homeostasis under both industrial and domestic conditions. This study describes, for the first time, the structure of the digestive tracts of two Anabantoidei fishes: African bush fish (Ctenopoma acutirostre) and paradise fish (Macropodus opercularis). The overall structure of the digestive tract and its histological structure were analyzed and compared in both fish species. Physiological predispositions indicated a predominance of omnivorous fish traits in M. opercularis in contrast to C. acutirostre, which has several morphological traits indicating greater adaptation to carnivory, particularly ichthyophagy. The results obtained will allow further research to be conducted in the future to optimize the nutrition and feeding of these fish and to develop appropriate dietary recommendations.
Keywords: digestive tract; environmental plasticity; fish histology; labyrinth fish.