The environmental toxicity of silver nanoparticles (AgNPs) is of increasing concern due to their intensified production, use and subsequent environmental release. To further understand nanoparticle toxicity, more knowledge is needed about the particle fate upon uptake. AgNPs were identified in both the GI tract and gill of fathead minnows using field-flow-fractionation interfaced to inductively coupled plasma mass spectrometry (FFF-ICP-MS).