Subnautica Wiki


Alien lifeforms may have unexpected applications. Utilizing alien resources is a proven survival strategy.

― PDA, Dialogue


The Bladderfish is a small, passive fauna species. It can be caught and is edible, mostly populating in the Safe Shallows and the Grand Reef.

The Bladderfish stands out in comparison to other small fish, as it can be used to craft Filtered Water. As a result, Bladderfish are a good source of H2O, though not as good as Disinfected Water and Large Filtered Water.

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

Eating a raw Bladderfish will restore fifteen points of Oxygen, which can save the player in certain situations. This only works in survival and hardcore modes.


The Bladderfish is a small creature comprised of a long, extremely thin main body with pale-purple coloured translucent bladders on top and bottom. These bladders have slim tubes protruding from their outer edges, the tips of which glow pink.

The Bladderfish's head is bright orange and ovular in shape, possessing a pair of large eyes and no mouth. The bladders have a faint violet bioluminescent glow. Its main body is reddish-pink with light green spots.


The Bladderfish swims by contracting and expanding its bladders, constantly altering its speed between fast and slow. Bladderfish shoals can currently only be found following Reefback Leviathans. At any other place they are mostly found alone or in very small groups.

The Bladderfish will flee from the player upon being approached.

Energy Value

Bladderfish.pngArrow-right (1).pngBioreactor.pngArrow-right (1).pngEnergy.png×210

Uses in Crafting

Bladderfish.pngArrow-right (1).pngFabricator.pngArrow-right (1).pngFiltered Water.png

Bladderfish.pngArrow-right (1).pngFabricator.pngArrow-right (1).pngCooked Bladderfish.png

Bladderfish.pngSalt Deposit.pngArrow-right (1).pngFabricator.pngArrow-right (1).pngCured Bladderfish.png

Silicone Rubber.pngBladderfish.pngArrow-right (1).pngFabricator.pngArrow-right (1).pngAir Bladder.png

Data Bank Entry


This unusual herbivore appears to be mostly defenseless, and bears little resemblance to the other lifeforms around it.

1. Semi-permeable Bladder:
The bladderfish is able to filter air and seawater into its body cavity through a unique membrane which surrounds its spine like a bladder. This allows it to remove and consume organic particulate caught on the way, and adjust its buoyancy.

2. Open-ended Vascular Tubing:
Can be angled and contracted to pump out water and achieve low-velocity, guided propulsion.

Largely oblivious to threats, and practically immobile at night, its only identified defense mechanism is that it's composed almost entirely of water, air and cartilage.

Assessment: Edible (oxygen may be retrieved from the bladder and added to tanks on consumption); membrane has applications as a natural water filter



  • The original name for this creature was Bladderfish. It was later changed to Airsack, but was then changed back to Bladderfish again in the PRAWN Update.