Piranhas are fishes that are members of the family Serrasalmidae. They are freshwater fish that inhabit South American rivers and lakes. Contrary to popular belief, not all piranhas are carnivores. Many, in fact, are omnivores that feed on the seeds, leaves, and fruits of plants, while other species feed solely on the slime and scales of other fishes. Curious about the evolution of body shape in piranhas, through collaborations with the University of Michigan Museum of Zoology, we worked with fish anatomy, rudimentary skeletal biomechanics, digital imaging, 2D x-rays and computed tomography data, phylogenetic comparative methods, and statistical coding using the R programming language to answer two essential questions: How do patterns of body shape integration differ across piranhas, and how do patterns of integration relate to diet and foraging ecology? In terms of diet, we predicted that predatory, carnivorous piranhas would be larger than omnivorous species. We hypothesized that piranhas will show weak patterns of interspecific integration, given considerable documented intraspecific integration. To answer these questions, we used 2D radiographic imaging to visualize piranha skeletons and geometric morphometric landmarking to assess body shape diversity across piranhas.