Deep Ecosystem — Bring the Ocean Alive

The ocean of Subnautica 2 is no longer a backdrop. It's a living, breathing food chain.

Deep Ecosystem gives every creature its own hunger, energy and fear. They act on it. They hunt when they're starving. They flee when something bigger shows up. They rest when they're exhausted. And they remember your presence.

What it does

Predators hunt.
When a NeedlerShark gets hungry enough, it locks onto the nearest prey and chases it down using the game's own pathfinding. No teleporting. No cheating. Real pursuit.

Prey flee.
Small fish detect predators within 80 meters and bolt in the opposite direction. They scatter when you drive your vehicle through their school.

Creatures rest.
After sprinting to escape or chase, creatures need to recover. You'll find them hovering still at the edge of a coral formation, vulnerable.

Predators defend territory.
Leviathans and sharks have territorial radii. Enter their space and they'll close in slowly as a warning. Stay too long and they attack.

The ecosystem self-balances.
A population regulator runs quietly every 5 minutes. If a species drops below 30% of its natural population, predators back off. Above 150% they hunt it more eagerly. The ocean finds its own equilibrium.

Your actions have consequences.
Drive a vehicle and creatures scatter 40 meters in every direction. Swim near small fish and they get nervous. Stay close to one long enough and it calms down. Build a base and the local wildlife moves away. Even harvesting fish gets counted.

Installation

Extract the DeepEcosystem folder and drop it into:
Subnautica2/Binaries/Win64/ue4ss/Mods/

Launch the game. No extra setup — UE4SS is already bundled with Subnautica 2.

Compatibility

No game assets are modified. Works alongside any other mod.

Under the hood

The AI runs on a 500ms tick, independent of the framerate. Up to 50 creatures run full behavioral AI simultaneously. The creature scan is cached every 3 seconds. Population state is saved to disk and restored when you load back in.