To study Tigertooth croaker (O. ruber) diets, monthly sampling was done from March 2015 to February 2016, using commercial fisheries in the Khoozestan coasts. Totally, 307 fish were examined. The average of gastro-somatic index, condition factor, intensity of fullness and the vacuity index were calculated as 0.1±0.01, 0.99±0.04, 167.89±54.83 and 50.1, respectively. Also, frequency of occurrence index for fish and shrimp as the preys were calculated as 82.1% and 19.8%, respectively. The Relative importance index of fish and shrimp were calculated as 9.53 % and 8.62%, respectively. The intestinal contents of Tigertooth croaker (O. ruber) contained fish belonging to mugilidae and shrimp of Penaeidea family. The results of present study in Khuzestan coasts showed that this species has the optimum condition factor of fullness in spite of weak index of nutrition. It can be suggested that Tigertooth croaker (O. ruber) is a tolerant species, adapted to the environmental condition in that despite receiving low amount of food, it would gain the enough energy to manage its growth and physiologic process. It is concluded in this study that the main food of Tigertooth croaker (O. ruber) was fish and the secondary food was shrimp.