Research Progress on the Toxic Effects and Mechanisms of Nanoparticles in Fish

Engineered nanoparticles (ENMs) released into aquatic ecosystems pose severe threats to farmed fish. This review systematically synthesizes the toxic effects and mechanisms of typical ENMs (metals, metal oxides, carbon-based materials, and quantum dots) on fish, which mainly induce oxidative stress, inflammation, apoptosis, and histopathological lesions, and disrupt ionoregulation, energy metabolism, and neurotransmission. The toxicity is modulated by nanoparticle physicochemical properties (size, charge, and surface modification), environmental conditions (pH, ionic strength, and natural organic matter), and fish biological traits (species and developmental stage). We assess practical mitigation strategies for aquaculture and identify critical knowledge gaps, aiming to improve ecological risk assessment and support the sustainable development of aquaculture. Importantly, we critically examine the substantial gap between laboratory exposure concentrations (typically mg/L) and environmentally relevant levels (ng/L to low-μg/L), highlighting the challenges this disparity poses for extrapolating laboratory findings to real-world aquaculture and natural ecosystems, and we identify priority research directions to bridge this gap.