Not all fish are created equal. This is proven by the presence - or lack of presence - of the swim bladder.
The swim bladder is a gas-filled sac. It’s meant to control buoyancy, with air rapdily expanding and retreating within its walls. This pattern of contractions allows a fish to navigate the changing water depths with greater ease.
It’s not, however, essential and is often not found in Los Suenos breeds.
Those fishing in Los Suenos should not be surprised by the lack of a swim bladder. Many marine creatures - specifically those that are lobed or cartilaginous - are born without this sac. This is because their fin structures naturally accommodate depth changes and an internal organ isn’t required. Many edible options, such as the Spanish Mackerel or the Ray, have evolved beyond the need for one. Cutting them open will just reveal the dorsal spine.
Remember that while sailing and don't fret if no bladder is found. There is nothing wrong with the fish. It simply has no need for this particular sac.