Subnautica Wiki

The Titan Holefish is a large fauna species. It lives in a symbiotic relationship with the Symbiote.


The Titan Holefish's body is mostly circular and laterally flattened. The body is mostly blue in color, darker towards the top and gradually lightening to white towards the bottom. The face portion of the body is a bright green and features two small blue eyes and a small, toothless mouth. The green coloration continues down the front of the body until it meets the tail fin. The tail fin is blue in color and very large, being taller than the entire body of the Titan though not very long.

The most defining feature of the Titan Holefish is the hole in the side of the body that the name is derived from. The hole is partially filled with a transparent light-blue gel whilst the center is completely empty, leaving a large enough gap for the player to swim through. The gel serves as a nest for the Symbiotes to lay their eggs within, affording protection and transferring essential nutrients and oxygen.


The Titan Holefish lives in a symbiotic relationship with a small aggressive fish known as the Symbiote. The Symbiotes lay their eggs within a gel-like substance in the Titan's tail hollow where the eggs are protected and can extract nutrients and oxygen. In return the Symbiotes remove parasites from the Titan's body and mob potential predators that approach the Titan. They swim around aimlessly, normally within sight of other Titans.

The player can use the Titan Holefish as an oxygen supply, similar to the Oxygen Plant. However, to approach the Titan Holefish, the player must avoid or fight off the Symbiotes surrounding the fish. The Titan Holefish is only useful as an emergency oxygen source, as the amount of oxygen is somewhat low and protected by Symbiotes.

Data Bank Entry

Titan Holefish
Titan Holefish Ency.png

A large, docile herbivore which emits oxygen and is defended by the small, aggressive symbiotes which accompany them.

- Slow, stupid and delicious
- Complex gills line the inside of the hole, drawing cold water in, and emitting warm, oxygen-rich water in its place
- Attracts symbiotes, which make the holefish their home and fiercely ward off any approaching lifeform
- Migrates more or less at random, feeding from nutrients deposited by the symbiotes

The titan holefish has evolved entirely beyond basic survival mechanisms like speed, intelligence or hunting. It exists in a semi-permanent state of unreflective calm, swimming forward on impulse, fully trusting the complex ecosystem which supports it.

Assessment: Valuable oxygen source, if you can reach it

Source: Scan Titan Holefish


The appearance of the Titan Holefish is heavily inspired by the ocean sunfish, or Mola mola, the largest bony fish on Earth. The relationship between the Titan Holefish and the Symbiotes somewhat resembles the relationship that cleaner wrasse have with various creatures from fish, to turtles.




  • The “Titan” part of the Titan Holefish’s name is not a size category like leviathan is.
  • The face of the Titan Holefish was added as a custom emote to the official Subnautica Discord server around one month before the creature was revealed to the public.
  • The Titan Holefish is a distant relative of the far smaller Holefish that lives within The Crater.
  • The Titan Holefish and the Symbiote have an inter-species mutualistic relationship, one of only four such relationships observed so far on Planet 4546B. The other three are between the Crabsnake and the Jellyshroom, the Crashfish and the Sulfur Plant, and the Ventgarden and the Spiral Plant.
    • The Titan Holefish-Symbiote relationship also constitutes the only known mutualistic relationship in the Subnautica universe that occurs between two different species of fauna.
  • The Titan Holefish's skeleton can be seen in its data bank entry and is shown to be extremely bizarre, with a bifurcated spine that extends around both sides of the eponymous hole and meets at the tail. Presumably this structure is shared with its smaller relative.