Does the swim blather of a fish generally keep positively neutrally or negatively buoyant?

The swim bladder, also called the gas bladder, is an organ found in most bony fish. It is an internal gas-filled sac which controls the fish's buoyancy. By adjusting the volume of gas in the bladder, the fish can ascend or descend in the water column without having to constantly swim. The swimbladder generally keeps the fish neutrally buoyant.