Plastic particles have been found present in almost all aquatic environments worldwide yet the specific threats they pose to both marine and freshwater biota remains unclear. Research on the toxicity of these particles has increased in recent years and has revealed that at environmentally relevant concentrations nanoplastic particles are taken up by aquatic organisms which can result in various toxic effects. Here, the impact of exposure to various sized nanoplastics was assessed using standard high throughput Zebrafish larval exposure paradigms. Using the fish embryo toxicity (FET) model and general and behavioural toxicity assay (GBT) larvae were exposed from 6-120 hours post fertilization (hpf) and 72-120 hpf respectively. The models were used to assess acute toxicity of 40-60 and 100 nm polystyrene nanoplastic particles. The analysis of the particle distribution via fluorescent microscopy was also used to confirm their uptake and accumulation within the larval zebrafish as well as their subsequent excretion. This testing provides insights into the ability of the larvae to uptake nanoplastic particles which will allow for a more in-depth analysis of their potential toxic effects on zebrafish larvae and potentially other aquatic biota.