6PPD-Quinone (6PPD-Q) was recently implicated in inducing mass pre-spawn mortality events in adult coho salmon (Oncorhynchus kisutch) in the Pacific Northwest. Since then, studies have reported highly variable toxicity among fish species, including within the salmonids. This dataset explores the sensitivity of coastal cutthroat trout (Oncorhynchus clarkii clarkii) at three different life stages: alevin, juveniles, and young of the year, and also includes analytically measured concentrations for the alevin and juvenile experiments.