Not every creature in Subnautica 2 wants to eat you. In fact, the vast majority of life in Sector Zero Omega is entirely passive — going about their own ecological business while you observe, scan, and occasionally harvest useful materials from them. Understanding these passive creatures is just as important as knowing the predators. Scans unlock critical blueprints, creature eggs provide sustainable food sources, and some passive fauna drop rare materials you cannot find anywhere else. This guide covers every passive creature currently discoverable in Early Access, where to find them, what scanning rewards they offer, and how they fit into the broader ecosystem.
Why Scan Passive Creatures?
Scanning is not just for completionists. Every creature scan in Subnautica 2 contributes to your PDA databank, and many scans unlock tangible gameplay benefits. Some creatures reveal hidden lore about the planet's history. Others unlock fabrication blueprints for advanced equipment, base modules, or food recipes. A few even provide direct material drops upon scanning completion — a mechanic new to Subnautica 2 that rewards thorough exploration.
Beyond rewards, scanning builds your ecological understanding. The PDA's creature entries explain predator-prey relationships, migration patterns, and symbiotic bonds. Knowing that a particular small fish school near Peepers means a Stalker is probably hunting nearby can save your life. Knowing which creatures process mineral deposits can lead you to resource-rich zones.
Always carry at least one spare battery for your Scanner. Many passive creatures spawn in schools of 6–12 individuals, and scanning the entire school often triggers a "complete school scan" bonus that grants extra Titanium or Copper Ore.
Surface & Shallow Water Passive Creatures (0–100m)
The starting biome and surrounding safe shallows are home to the most accessible passive fauna. These creatures are ideal for early-game scanning because they pose no threat and are abundant.
| Creature | Habitat | Scan Reward | Useful Drop |
|---|---|---|---|
| Peeper | Safe Shallows, Kelp Forest | Peeper Data Bank entry | Peeper flesh (cooked: +32 food) |
| Bladderfish | Safe Shallows, Grassy Plateaus | Filtered Water recipe unlock | Bladder (crafts into Filtered Water) |
| Garryfish | Safe Shallows | Garryfish data, minor lore | Garry flesh (+18 food) |
| Hoopfish | Safe Shallows, Kelp Forest | Hoopfish school behavior data | Hoopfish flesh (+15 food) |
| Hoverfish | Kelp Forest caves | Hoverfish lure mechanics | Hoverfish flesh (+20 food) |
| Boomerang | Safe Shallows, Grassy Plateaus | Boomerang migration paths | Boomerang flesh (+21 food) |
| Rabbit Ray | Safe Shallows, Grassy Plateaus | Rabbit Ray ecology entry | Rabbit Ray egg (decorative + bioreactor fuel) |
| Jellyray | Grassy Plateaus (daytime) | Jellyray bioluminescence data | Jellyray egg, bioluminescent gel |
The Peeper — Your First Scan
The Peeper is the most iconic passive creature in Subnautica 2 and the first one most players scan. Its large, singular eye is not just for show — Peepers have the highest visual acuity of any shallow creature and serve as an early warning system. When a predator enters the area, Peepers scatter in a visible panic pattern. Learning to read this behavior lets you detect threats before you see them.
Peepers also play a unique ecological role: they consume loose mineral fragments and excrete small quantities of Silver Ore. Following a dense school of Peepers can occasionally lead to Silver deposits that would otherwise be difficult to spot. Their scan is unremarkable in terms of direct rewards, but the behavioral knowledge pays dividends throughout the game.
Bladderfish — Early Survival Essential
Among all shallow creatures, the Bladderfish is arguably the most important for early survival. Its internal air bladder contains filtered, drinkable water — and scanning one unlocks the Filtered Water crafting recipe in your Fabricator. Before you build a Water Filtration Machine, Bladderfish are your primary renewable water source. Each Bladderfish converts into one unit of Filtered Water, and they respawn rapidly in Safe Shallows.
Bladderfish despawn in deeper waters. If you are hauling them to a base below 200m, transfer them to an aquarium or storage immediately. Uncollected Bladderfish corpses sink and vanish after 90 seconds.
Mid-Depth Passive Creatures (100–300m)
As you venture deeper, passive creatures become larger, stranger, and more valuable. Many mid-depth species are found only in specific biomes, making them easy to miss if you do not explore thoroughly.
| Creature | Habitat | Scan Reward | Useful Drop |
|---|---|---|---|
| Reginald | Grassy Plateaus, Sparse Reef | Reginald schooling AI data | Reginald flesh (+44 food, best in game) |
| Spadefish | Kelp Forest, Grassy Plateaus | Spadefish defensive posture data | Spadefish flesh (+23 food) |
| Symbiote Shrimp | Twilight Zone walls | Symbiotic relationship lore | Symbiote enzyme (medical crafting) |
| Crescent Fish | Twilight Zone open water | Crescent migration timing | Crescent flesh (+28 food) |
| Deep Shoom | Cave systems (150–250m) | Fungal ecosystem entry | Spore cluster (bioreactor fuel) |
| Lantern Fish | Twilight Zone (night) | Bioluminescent efficiency data | Lantern egg, phosphorous residue |
| Rockgrub | Cave floors, rocky walls | Rockgrub mineral digestion lore | Calcium deposit, small chance of Lead |
Reginald — The Best Food Source
The Reginald is the single most efficient food source in Subnautica 2. A cooked Reginald restores 44 food points — more than double most other fish. They school in large groups in the Grassy Plateaus and are completely passive, making them ideal for setting up a farm. Scanning Reginalds unlocks their behavioral data but more importantly, scanning a school of five or more unlocks the Alien Containment egg recipe for Reginalds, letting you breed them indefinitely in a base aquarium.
Rockgrub — The Hidden Miner
Rockgrubs are small, slow-moving creatures that cling to cave walls and rocky outcrops. They are easy to overlook because they blend into stone textures, but they are uniquely valuable. Rockgrubs digest minerals and occasionally excrete small calcium deposits. More importantly, completing a scan of five Rockgrubs unlocks the Mineral Detector upgrade for your Scanner — a tool that highlights nearby ore deposits through walls.
Deep & Abyssal Passive Creatures (300–800m)
Deep biomes are not only home to leviathans. Several entirely passive species inhabit the abyss, adapted to extreme pressure, near-total darkness, and scarce food sources. These creatures are some of the most rewarding scans in the game.
| Creature | Habitat | Scan Reward | Useful Drop |
|---|---|---|---|
| Abyssal Ray | Deep Grand Reef, Lost River entrance | Pressure adaptation biology | Abyssal Ray egg, diamond dust |
| Ghost Fish | Lost River corridors | Ghost Fish transparency mechanics | Ghost scale (cloaking module material) |
| Thermal Plume Worm | Lava Zone vents | Extremophile biology entry | Thermal enzyme (power cell crafting) |
| Void Jellies | Crater Edge (void) | Void ecology fragment | Jelly membrane (advanced silicone) |
| Deep Lily | Lost River, Deep Reef | Plant-animal hybrid classification | Lily nectar (biofuel concentrate) |
Ghost Fish — Cloaking Material Source
The Ghost Fish is a remarkable translucent creature found exclusively in Lost River corridors. Its skin contains micro-structures that bend light around its body — a biological cloaking mechanism. Scanning Ghost Fish unlocks the Stealth Module blueprint for the Seamoth, which reduces enemy detection range by 40%. Each Ghost Fish also drops one Ghost Scale, a rare crafting material required for the Stealth Module and the advanced Perimeter Defense upgrade.
Ghost Fish are nearly invisible unless you use your flashlight. Their faint silhouette only becomes visible under direct light. Sweep your flashlight across Lost River walls and you will spot their drifting, ghostly forms.
Ecosystem Roles and Interactions
Passive creatures in Subnautica 2 are not isolated entities — they participate in a complex food web. Understanding these relationships helps you predict where creatures will spawn and how ecosystems respond to your presence.
Cleaning Symbiosis
Several small passive creatures — Symbiote Shrimp and certain small fish — engage in cleaning symbiosis with larger predators. They eat parasites and dead skin off aggressive creatures. This means you will often find safe-to-harvest passive creatures in close proximity to dangerous predators. The predators ignore the cleaners, but they will not ignore you. Approach these zones with caution.
Mineral Cycling
Creatures like the Rockgrub, Peeper, and Thermal Plume Worm participate in mineral cycling. They consume inorganic material and either concentrate it into collectible form or transport it across biomes. Following Rockgrubs has led many players to hidden Cave Sulfur deposits. Following Peepers can reveal Silver Outcrops that are otherwise camouflaged against sand.
Bioluminescent Signposting
Many deep passive creatures use bioluminescence for mating and schooling. These light patterns act as unintentional signposts for players. A dense cluster of Lantern Fish usually indicates the edge of a cave entrance. A trail of Abyssal Rays often marks a safe route through an otherwise confusing trench system. Learn to read these biological signals and navigation becomes significantly easier.
Scan Completion Checklist
For completionists aiming to fill every entry in the Creature Data Bank, here is a prioritized checklist:
- Safe Shallows sweep — Peeper, Bladderfish, Garryfish, Hoopfish, Boomerang, Rabbit Ray (6 scans)
- Kelp Forest sweep — Hoverfish, Hoopfish (shared), Spadefish, Stalker (aggressive but needed for completion)
- Grassy Plateaus sweep — Reginald, Boomerang (shared), Rabbit Ray (shared), Jellyray, Spadefish (shared)
- Twilight Zone sweep — Symbiote Shrimp, Crescent Fish, Lantern Fish, Deep Shoom
- Cave systems sweep — Rockgrub, Hoverfish (shared), Deep Shoom (shared)
- Lost River sweep — Ghost Fish, Abyssal Ray, Deep Lily
- Lava Zone sweep — Thermal Plume Worm (requires heat protection)
- Void Edge — Void Jellies (extreme danger, prepare thoroughly)
Summary
Passive creatures are the backbone of Subnautica 2's living world. They provide food, water, crafting materials, blueprints, and ecological intelligence. Scanning them thoroughly is not busywork — it is a direct investment in your survival. Prioritize Bladderfish and Reginald for sustenance, Rockgrubs for the Mineral Detector, and Ghost Fish for the Stealth Module. Respect their roles in the ecosystem, and they will reward you with everything you need to survive the depths.