Davis and Boyd 32 and Gonzalez et al. 18 found positive, negative, and non-significant relationships between single elements and body size in fish and invertebrates. Sterner and George 35 and El-Sabaawi et al. 26 found mixed (negative and non-significant) support for body nutrient content and body size relationships in fish. Others, including Fagan et al. 14 and Lemoine et al. 17 , found mixed and weak support across groups of invertebrates. Second, the trophic status of organisms has been identified as a useful predictor of body nutrient content in arthropods and other invertebrates 18,25 , temperate and tropical fishes 15 , and across other taxa 17. This suggests that organisms, over evolutionary time, reduced the stoichiometric imbalances between their body tissues and their prey to maximize utilization of their food resources 36. This concept is a basic tenet of Ecological Stoichiometry Theory (EST) and suggests that animals within trophic groups are inherently limited by the quality of their food resource (plant matter is rarely as nutrient-rich as animal tissue) 19 , and body nutrient composition has indeed been shown to largely reflect diets 16,26,37. For example, herbivores and detritivores feed on resources with high C:nutrient ratios, and also tend to have higher body C:nutrient ratios than organisms at higher trophic levels 15,18,38. This suggests an inverse relationship between trophic position and body C:nutrient ratios. A third avenue for predicting organismal body nutrient content is using one body nutrient to predict another, i.e., examining how nutrients covary. Hendrixson et al. 15 found relationships between body content of C and P were negatively correlated across multiple species of temperate fishes. This approach has not received widespread attention (but see 18), but does offer important insight into the degree to which elements are fundamentally linked, whereby the demand for one nutrient coincides with the demand for another 15,38-40 , herein termed "stoichiometrically linked. " One expectation would be a negative relationship between elements, as found by Hendrixson et al. 15 , as this suggests net conservation of elemental mass-balance, whereby increases in one nutrient results in reductions in another. Further, if trophic group is a good predictor of body stoichiometry then the relationship (i.e., the slope) by which elements are stoichiometrically linked may differ across trophic groups or other levels of classification that have large differences in body nutrient content. One example of this is the difference between vertebrates and invertebrates, whereby the P-rich internal skeleton of vertebrates should lower body C:P and N:P ratios, and thus generate relationships between these pairs of elements with steeper slopes. We take advantage of a large dataset of somatic carbon (C), nitrogen (N), phosphorus (P), and their ratios for 738 individuals of 105 invertebrate and vertebrate species (52 families, 68 genera) in a single tropical marine community to test for predictive relationships...