The olfactory system in fish plays a crucial role in various behaviors, including feeding, mating, navigation, and predator avoidance. Central to this system is the olfactory mucosa, a specialized tissue responsible for detecting chemical cues in the aquatic environment. This comprehensive review aims to provide an in-depth analysis of the status and functionality of olfactory mucosa in fish. We begin by exploring the anatomical and histological characteristics of the olfactory mucosa across different fish species. Next, we delve into the physiological mechanisms underlying olfaction in fish, including odorant reception, signal transduction, and neural processing. Furthermore, we examine the role of olfactory mucosa in mediating crucial ecological interactions, such as foraging strategies, social behaviors, and habitat selection. Additionally, we discuss the impact of environmental factors, such as pollution and habitat degradation, on the structure and function of the olfactory mucosa in fish. Finally, we highlight current research trends, technological advancements, and future directions in the study of fish olfaction and its implications for conservation and management strategies. Through this comprehensive review, we aim to enhance our understanding of the intricate relationship between olfactory mucosa and fish behavior, ecology, and sensory ecology.