Bladderfish (Subnautica)

The Airsack, also known as the Bladderfish, is a life form belonging to the fauna category.

It is catchable, harvestable and edible. They are most commonly found in the Safe Shallows biome. They stand out in comparison to other small fishes, as they can be used to craft filtered water, which fills up 20 H2O. As a result, Airsacks are the second best source of H2O, after disinfected water. When in Freedom mode, you can click on it to replenish your oxygen.

Being slow and passive, Airsacks are very easy to catch, especially during night time, when they are next to immobile due to their diurnal properties.

Appearance
The Airsack is a small fish comprised of a long, extremely thin main body with large translucent bladders on the top and bottom. These bladders have slim tube-like structures protruding out from their outer edges, and they undulate as the Airsack moves.

The Airsack's head is very bright orange and ovular in shape, possessing a pair of large eyes and no discernible mouth. Its bladders appear to have a dull purple bioluminescent glow.

Data Bank Entry
Assessment: Membrane may have applications as a natural water filter
 * 1) Semi-permeable membrane: Body consists of an oxygen- and water-filled, semi-permeable membrane. No oral cavity detected. Membrane may filter plant matter from the water.
 * 2) Open-ended vascular tubing: Can be angled and contracted to pump out water and achieve low-velocity, guided propulsion. No fins identified.
 * 3) Mostly oblivious threats, its only identified defense mechanism: it is 95% cartilage.