The study investigated the effect Zinc Oxide nanoparticle structures on the toxicity and teratogenicity towards zebrafish. Varying structures of Nano-Zinc Oxide crystals were synthesized at sizes similar to commercially available 50 nm to 100 nm particles and exposed to zebrafish embryo for a span of 5 days conducting toxicity and teratogenicity assay. While previous studies debated the result of commercially available Zinc Oxide nanoparticles, the synthesized Nano-Zinc Oxide demonstrated definite toxicity. An interesting finding showed that at higher concentration the zebra fish were eradicated at an early stage of the experiment but lower concentration created higher mortality rate in the end.