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 mode.


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

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 red 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 Reefbacks. At any other place they are mostly found solo or in very small groups.

The Bladderfish will flee from the player upon being approached.

Uses in Crafting

BladderfishArrow-right (1)FabricatorArrow-right (1)Filtered Water

BladderfishArrow-right (1)FabricatorArrow-right (1)Cooked Bladderfish

BladderfishSalt DepositArrow-right (1)FabricatorArrow-right (1)Cured Bladderfish

Silicone RubberBladderfishArrow-right (1)FabricatorArrow-right (1)Air Bladder

Energy Value

BladderfishArrow-right (1)BioreactorArrow-right (1)Energy×210

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.