Corals live across a range of nutritional and environmental gradients. The physiological traits of corals influences their ability to obtain resources across these environmental gradients and ultimately determines their biochemical niche. Importantly, this biochemical niche extends beyond the more commonly studied resources of carbon:nitrogen:phosphorous and includes trace elements such an zinc, copper, manganese, potassium, strontium and iron (to name a few). We introduce the concept of the coral elementome through unique data demonstrating how the elementome changes for key coral taxa in relation to resource availability across a range of reef environments and future temperature scenarios. We combination analytical techniques dedicated to studying coral holobionts, including elemental bioimaging with laser ablation-inductively coupled plasma - mass spectrometry (LA-ICP-MA), ICP-MS, metabolomics and physiological diagnostics. By studying corals living in naturally extreme environments and coupled with lab-based experimentation we are able to: (i) identify how coral biochemical-niches change over space and time, (ii) establish how the Symbiodiniaceae elementome may contribute to broader holobiont fitness, and (iii) discuss how future environmental change may impact the coral elementome and in turn the form and functioning of coral reefs.