Tetracycline toxicity in fish: Recent insights into physiological and health implications.

Tetracyclines (TCs), a class of broad-spectrum antibiotics widely used in aquaculture, pose significant risks to fish health because of their environmental persistence and tendency to bioaccumulate in aquatic systems. This review synthesizes the toxic effects of TCs across key fish species (e.g., Danio rerio, Cyprinus carpio). TCs compromises respiratory efficiency via gill lamellar fusion, induces intestinal atrophy and inflammation, and alters hematological profiles, impairing oxygen transport and immune function. Biochemically, it disrupts antioxidant defenses, leading to pervasive oxidative stress. At the molecular level, TCs induces genotoxicity. Early life stages exhibit developmental toxicity (e.g., spinal deformities). Immunologically, TCs suppresses phagocytic activity and cytokine release, heightening infection susceptibility. Furthermore, it interferes with bone mineralization and causes muscle degeneration. Overall, TCs contamination represents a substantial threat to fish health and aquatic food webs, necessitating stricter regulations and improved removal strategies.