Global climate change is one of the most significant threats to biological diversity and survival. Coupled with increasing anthropogenic outflows and environmental devastation, temperate species must adapt or move north to maintain temperature homeostasis. Polar areas are the most critically impacted, with the Arctic warming several-fold faster than other areas. This alter ice coverage and permafrost depth, revealing deposits of critical minerals, including those used in battery technologies, such as zinc, cobalt, and nickel (Ni). In response to the growing demand for green energy technologies, significant extraction efforts have led to increased aquatic metal concentrations in the Arctic. Exploitation of these mineral resources allow for increased transport of these metals into Arctic waters, yet insufficient data exists regarding the impacts they may have on Arctic biota. This study aimed to address some of these knowledge gaps, with a particular interest in the impacts of Ni on Arctic char (Salvelinus alpinus). Arctic char are an important salmonid species in Arctic ecosystems, but the physiological responses of these fish to chronic Ni exposure remains unstudied. To address this, we exposed juvenile Arctic char to environmentally relevant Ni concentrations for sixty days to investigate the physiologic consequences of exposure and the mechanisms of toxic action. This work evaluated impacts on growth, survival, the respiratory system, and ionoregulation, finding significant impacts on both survival and growth, among other effects. These results provide insight into the physiological consequences of Ni exposure on Arctic char and the risk posed to these fish in their native environments.