“Fish are statically unstable.” This statement is often the starting point for discussions about stability in fishes. Its validity is immediately accepted by both scientists and children. Both have seen that when their test subjects or pets are anesthetized or die, they tend to go “belly up.” Without using their fins constantly, many species of fishes are unable to maintain a dorsal-side up orientation. The mechanism behind this instability has also been proposed. A buoyant force pushes up on the fish at its center of buoyancy (COB), which is thought to lie below the center of mass (COM). Like a pencil standing on its point, this configuration is unstable; any small deviation causes a torque that tends to flip the fish upside-down. While this mechanism makes sense, we have relatively little data on the true locations of these two critical points in different species or the torques generated from their displacement. Moreover, many fish can adjust the buoyant force and the distance between COM and COB by inflating their swim bladders. We used computed tomography (CT) scans and photogrammetric imaging to construct 3D models of several species of fishes to locate the COM and the COB of each individual. Using photogrammetry, we found variation between species. In trout, COM is indeed below COB, but in bluegill, for instance, COM is in front of COB, not below, and in perch, COM is diagonally below and in front of COB. For all species examined, the distance between the two points was quite small, resulting in small destabilizing torques. Here we present results based on CT scans on the role of the swim bladder in controlling the distance between COM and COB.