Wireless capsule endoscopy (WCE) plays a significant role in the non-invasive small intestine screening for obscure gastrointestinal bleeding detection. However, the task of reviewing 60,000 frames to detect the bleeding encumbers the clinician, leading to visual fatigue and false diagnosis. In this paper, we propose a color feature based bleeding detection system with feature selection using a modified ant colony optimization (MACO) algorithm. We have utilized the feature selection capability of MACO algorithm to find the optimum feature subset over the color space of RGB and HSV, which provided a classifier that outperforms the classifier formed from RGB and HSV features individually. Comprehensive experimental results reveal that the proposed MACO algorithm can detect the optimal feature subset with performance comparable to exhaustive search in case of individual classifier from RGB and HSV requiring 2% of the computational time compared to exhaustive search. The comparative study of feature selection showed that MACO can provide the most relevant features and improve the performance in terms of accuracy, sensitivity and computational time.