Distribution of CuO nanoparticles in juvenile carp (Cyprinus carpio) and their potential toxicity

► CuO NPs had no acute toxicity to carp while carp growth was inhibited during the sub-acute toxicity tests. ► CuO NPs distribution followed an order: intestine > gill > muscle > skin and scale > liver > brain. ► Carps could actively eliminate CuO NPs through excrements to lower the toxicity. ► Cholinesterase activity of brain tissues was inhibited after NPs exposure, suggesting neurotoxicity potential of CuO NPs to fish.