Fish body shape is a complex morphological trait that affects swimming, feeding, and defense from predators. Fish exhibit a wide range of body shapes that reflect different ecological and evolutionary pressures. Deep, laterally compressed bodies have evolved multiple times in different families. Functional hypotheses explaining these trends include predator defense and increased maneuverability. While there is solid evidence that increasing body-depth helps fish avoid certain types of predators, the evidence that body shape increases a fish’s maneuverability is ambiguous. We used a two-pronged approach to explore the effects of body shape on the control of maneuvers using both live fish and a robotic model that allowed us to independently vary body shape. We captured ventral video of blood-fin and black-skirt tetras performing a wide range of maneuvers and we tested the robotic model’s turning ability at a range of different input kinematics across three body shapes. We found no differences in maneuverability performance between two species despite significant difference in body shape. Conversely, we found that deepening bodies increase the robot’s ability to change direction and accelerate, though acceleration exhibits diminishing returns beyond a certain body depth. By using a robotic model, we were able to isolate the effects of body shape on maneuverability and clarify this confounded relationship. Studying the functional morphology of complex traits such as body shape and their interaction with complex behaviors like maneuverability benefit from both the broad view provided by comprehensive comparative studies, and the control of variables enabled by robophysical experiments.