Comparative Morphology of the Digestive Tract of Anabantoidei Fishes Inhabiting Asian and African Freshwaters

Anabantidae is a large and diverse group of fish cultured both under aquaculture conditions and as hobbyists. 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 to date 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 bushfish (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. In conclusion, it was shown that physiological predispositions indicate a predominance of omnivorous fish traits in the M. opercularis, in contrast to the C. acutirostre, which has several morphological traits indicating a 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.