Capillaria infections extend beyond terrestrial animals to impact aquatic organisms, particularly fish in aquaculture settings. Various Capillaria species can infect fish, causing diseases known as capillariasis. Common in both freshwater and marine environments, these infections may result in reduced growth rates, poor feed conversion, and increased mortality among fish populations. In aquaculture, Capillaria infections pose economic challenges due to their impact on fish health and production. Infestations often occur when fish are raised in crowded conditions or when water quality is compromised. Prevention strategies include maintaining optimal environmental conditions, practicing good aquaculture management, and implementing regular health monitoring. Research into the life cycle, transmission, and host specificity of Capillaria species in aquatic environments is crucial for developing effective control measures. As the aquaculture industry continues to grow, understanding and mitigating Capillaria infections in fish contribute to sustainable and healthy aquaculture practices.