Titan Holefish

The Titan Holefish is a large fauna species that will appear in Subnautica: Below Zero. It lives in a symbiotic relationship with the Symbiote.

Appearance
The Titan Holefish's body is roughly 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 hollowed out section of the body that the name is derived from. The hollow 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.

Behaviour
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.

The player can use the Titan Holefish as an oxygen supply, similar to the Oxygen Plant.

Design
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.

Trivia

 * The “Titan” part of the Titan Holefish’s name is not a size category like leviathan is.
 * The face of the 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.
 * It is a distant relative of the far smaller Holefish that lives within The Crater.
 * The Titan Holefish and the Symbiote are the third creatures shown to be in a symbiotic relationship, the first two being the Crashfish/Sulfur Plant, and the Crabsnake/Jellyshroom from Subnautica.