This paper presents data about several digestive tract morphometric for three omnivore cyprinid
fish species, Prussian carp (Carassius gibelio), Chub (Squalius cephalus) and Cactus roach (Rutilus
virgo) from river Sava in order to bring the obtained information in relationship with the type of food that
fishes use. Standard body length, body weight and digestive tract length and weight were measured. The
maximum value for digestive tract length in comparison to the standard length of the body was
determinate for Prussian carp (483,61%) which indicate that herbal component has a significant role in its
diet. Much lower values were observed for Chub and Cactus roach (157,41% and 151,11%) which
indicates higher share of animal food in their diet. All analyzed fish species showed a high positive
correlation between the standard body length and the absolute length of the digestive tract, as well as
between body mass and weight of the digestive tract.
