Why do some fish not have a swim bladder?
Some species don’t need a swim bladder because they spend all their life skimming along the ocean floor. Other fish, such as rays and sharks, ascend and descend by propelling themselves forward. Just as in an airplane, the movement of fluid under the fins creates lift, which pushes the fish upward.
Do fish have swim bladders?
You might be surprised to hear most bony fishes have a special organ to help them with that: a swim bladder. This is a thin-walled sac located inside the body of a fish that is usually filled with gas.
Can a fish survive without a swim bladder?
If your fish has a permanent swim bladder disorder, they can still live a full and happy life with some lifestyle modifications. With positively buoyant fish, some of the fish’s body can spend too much time above the water’s surface, making it important to keep their skin moist.