Inspired by the social behavior of cockroaches, the Roach Infestation Optimization (RIO) algorithm was developed, utilizing three primary behaviors of cockroaches: seeking the darkest location, socializing with nearby cockroaches, and experiencing hunger, which prompts them to leave their comfort zones. These behaviors, combined with evolutionary algorithms, yield more satisfactory results. To further enhance RIO’s performance, an adaptation of the Cmax parameter representing the cognitive and social adjustment was introduced to balance exploration and exploitation, thereby improving algorithm convergence. As a result, the RIO algorithm with fuzzy adaptation outperformed the original RIO when evaluated using various benchmark mathematical functions.