Abstract: Active sensing organisms, such as bats, dolphins and electric fish, generate a 3D space for active sensation by emitting self-generated energy into the environment. For a weakly electric fish, we demonstrate that the electrosensory space for prey detection has an unusual, omnidirectional shape. We compare this sensory volume with the animal’s motor volume⎯the volume swept out by the body over selected time intervals and over the time it takes to come to a stop from typical hunting velocities. We find that the motor volume has a similar omnidirectional shape, which can be attributed to the fish’s backwards-swimming capabilities and body dynamics. The electrosensory space for prey detection is assessed by analyzing simulated changes in spiking activity of primary electrosensory afferents during empirically measured and synthetic prey capture trials. The animal’s motor volume is reconstructed from video recordings of body motion in the same prey capture study. To our knowledge, this study is the first to quantitatively compare 3D sensory and motor volumes in any organism. Our results suggest that in weakly electric fish, there is a close connection between the shape of the sensory and motor volumes. We consider three general spatial relationships between 3D sensory and motor volumes and test hypotheses about how these relative geometries affect behavioral control strategies.