Nanomaterials (NMs) are being widely incorporated into a variety of fields such as medicine, cosmetics and electronics, due to the exceptional and unique qualities provided by their small size and high surface area to volume ratio. The increased use of NMs leads to their inevitable deposition into environmental waters where they interact with environmental organisms such as the fresh water zooplankton Daphnia manga (D. manga). D. magna is an ideal candidate for fresh water toxicity testing and a central study species used by the Organization for Economic Cooperation Development (OECD) which sets the gold standards for eco-toxicity testing protocols. These protocols, specifically OECD 202 (short term acute test) and OECD 211 (long term chronic test) using D. magna were originally designed for bulk chemicals though have recently been deemed acceptable for NM testing, despite NMs existing as suspensions rather than dissolved chemicals. These protocols also fail to account for key exposure features of relevance for nanomaterials, such as fact that the natural clearance processes in these organisms require access to food to push out previously accumulated matter, and the fact that under realistic exposure scenarios the NMs will have acquired a corona of biomolecules that changes their identity, stability towards agglomeration, uptake and excretion. Thus, the lack of biomolecules added to the medium, and feeding during / post exposure can lead to significant over or underestimation of the amount of NMs taken up or retained within D. magna which can lead to uncertainty of dose and ultimately miscalculation of NMs toxicity and the risks posed by these materials. Herein we present evidence to support the call for revised guidelines for D. magna acute and chronic toxicity tests for NMs.