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 fishes, as they can be used to craft Filtered Water. As a result, Bladderfish are a good source of H₂O, though behind 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 constantly 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 by them.

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×400

Data Bank Entry


This unusual herbivore appears mostly defenseless.

  1. Semi-permeable Membrane:
    This lifeform is able to filter seawater into its body cavity through a unique membrane, removing and consuming organic particulate caught on the way.
  2. Open-ended Vascular Tubing:
    Can be angled and contracted to pump out water and achieve low-velocity, guided propulsion.

Largely oblivious to threats, its only identified defense mechanism: it is 95% cartilage.

Assessment: Membrane may have 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.