Oxygen Not Included: Survival Guide

A practical colony-building guide for Klei's Oxygen Not Included: how to survive your first 20 cycles, then build sustainable oxygen, food, power, and temperature control, handle germs and stress, and reach the midgame. It also covers what each DLC adds, including the 2026 Aquatic Planet Pack.

Researched September 2026. Current as of game update 744825 (July 28, 2026), after The Aquatic Planet Pack launched on June 11, 2026. Live games change, so check the linked sources if something differs.

Quick Start

1. Pause constantly. Space bar pauses. ONI is a planning game, and most disasters come from queueing things at full speed.
2. Pick good Duplicants at the Printing Pod. Look for interests in Digging, Building, and Research on the first three, and avoid crippling traits (see the table below). Reroll freely at the start.
3. Build in this order in the first few cycles: Research Station, then Manual Generator + a Battery, then Outhouse + Wash Basin, then Cots, then a food source (Microbe Musher or a Mealwood farm).
4. Oxygen comes later than you think. The starting biome has plenty of oxygen plus Oxylite and algae. Build an Algae Deoxidizer early, then move to an Electrolyzer setup by the midgame.
5. Keep your base compact and dig a little at a time. Open caverns let CO2 (which sinks) and hot gas flood your base.
6. Watch the Colony Summary's warnings (Food, Oxygen, Stress). They're your early warning system.
7. Temperature is the long-term killer. Machines produce heat. Plan to insulate and delete heat (see Temperature below).
8. Rooms give morale. A proper Latrine, Barracks or Bedroom, and Mess Hall make a big difference to stress.
9. Save often and keep multiple saves. Autosave is on, but an extra manual save before big projects is cheap insurance.

Choosing Duplicants

Note: Iron Gut resists food poisoning, and Mole Hands speeds up digging. Check each trait's tooltip, since the exact effects vary more than this table can show.

Oxygen

The classic midgame setup (SPOM): An Electrolyzer in a sealed room. Gas Pumps send oxygen into the base and hydrogen into a Hydrogen Generator, which powers the pumps and electrolyzer. A Gas Filter or element sensors sort the gases. There are dozens of community designs. Search for "SPOM" and pick one you understand.

CO2 sinks. Let it pool at the bottom of your base, then remove it with a Carbon Skimmer (water + CO2 → polluted water) or by ranching critters (for example, Slicksters eat CO2).

Food

Rules of thumb:

• Refrigerate food. Refrigerators slow rot. Storing food in a sterile atmosphere (CO2 or vacuum) and cold temperatures stops it entirely.
• Cooked food gives more calories per plant and better morale. Get the Electric Grill early.
• Farm Tiles and Hydroponic Farms in a proper Farm (greenhouse) room give a growth bonus.

Water, Plumbing, and Toilets

• Start with the Outhouse (makes polluted dirt, which needs emptying) and Wash Basin, then upgrade to the Lavatory + Sink once you have plumbing.
• A Lavatory room with a Sink and no other clutter is a Washroom, which gives a morale bonus.
• Lavatories produce polluted water. Run it through a Water Sieve (needs sand) to get clean water back. This closed loop keeps the colony alive.
• Use Liquid Pumps, Pipes, Liquid Valves, and Bridges to route water. The Plumbing overlay shows flow direction.
• Food poisoning germs live in polluted water and toilets. Keep Wash Basins or Sinks on the exit path from toilets.

Power

Wiring rules:

• Normal Wire handles 1 kW. Heavi-Watt Wire carries more but hurts decor and can't pass through buildings. Conductive wire variants exist, and with the Aquatic Planet Pack, rubber insulated conductive wire (4 kW) becomes available.
• Too much draw on a wire overloads it and damages it. Use Transformers to split circuits.
• Smart Batteries plus automation let generators run only when needed.

Temperature

Every building adds heat. Liquids and gases carry it. ONI's midgame is mostly about moving heat out.

• Insulated Tiles (ideally from Igneous Rock or better, Ceramic or Insulation) wall off hot areas.
• Machine rooms: Put electrolyzers, generators, and refineries in insulated rooms, away from farms.
• Heat deletion: An Aquatuner cooling a coolant loop, dumped into a Steam Turbine chamber, is the standard late-game cooler. Wheezeworts and the Ice-E Fan are early stopgaps.
• Crops have temperature ranges. Mealwood and Bristle Blossom die if the farm overheats.
• Material matters: Low-conductivity materials insulate. Metals transfer heat.

Stress, Morale, and Rooms

Each Duplicant's morale must stay at or above their expectations, which rise with learned skills.

Stress responses when morale falls short:

• Destructive breaks buildings. Ugly Crier stops and cries. Binge Eater eats your food. Stress Vomiter spreads germs.
• Fix stress with rooms, better food, decor (paintings, sculptures, plants), a Massage Table, and downtime in the schedule.

Germs and Disease

• Food Poisoning: From polluted water and dirty hands. Wash Basins and Sinks prevent it.
• Slimelung: From polluted oxygen, the gas that comes off slime. Avoid digging slime near the base, and use a Deodorizer.
• Zombie Spores (later biomes): Very dangerous. Chlorine, Bleach Stone, and extreme heat (above roughly 290 °C) kill them, and they die in liquids. They linger for a long time in oxygen.
• Medical: A Sick Bay, Apothecary, and the Medicine skills. Germs die in chlorine and at extreme temperatures.

Research Priorities

1. Basic Farming and Meal Preparation (food)
2. Power Regulation (better batteries and wire)
3. Plumbing and Sanitation (Lavatory, Sink, Water Sieve)
4. Air Systems (Electrolyzer, gas pumps and pipes)
5. Ranching (Grooming Station, critter food)
6. Temperature Modulation (Insulation, Space Heater, Ice-E Fan)
7. Mid-game: Refined Objects, Distillation, HVAC, Liquid Temperature (Aquatuner), and Space research for rockets

Tech names can shift between DLC and base game research trees. Hover each node for what it unlocks.

Ranching Basics

• Hatches eat rock and minerals and give coal plus meat. They're the easiest first ranch.
• Pacu (fish) give Pacu fillets and eat algae or seeds.
• Pufts turn polluted oxygen and other gases into slime, algae, and other materials.
• Dreckos give Reed Fiber and meat. Shine Bugs give light.
• A Grooming Station keeps critters happy (more eggs). Keep populations in check with Critter Drop-Offs and automation.

DLC Overview

Aquatic Planet Pack notes

• Duplicants learn to swim through skills (Basic Swimming, Divemaster), and they can perform CPR.
• Marinea (plus Marinea Minor and Fragment variants) is a flooded start where dry land is scarce.
• Rubber (from palm-tree latex, via the Vulcanizer) makes rubber boots, 4 kW insulated conductive wire, and Gaskets for submersible buildings.
• New biomes: Beach, Reef, Kelp Forest, and Abyss. The Tidal Turbine adds a water-based power option.
• New critters include Beakons, Seaquines (milked at the Aquatic Milking Station for Caviar), Blowters, Glo Squids, Slogo snails, and giant clams that yield pearls.
• A Breathing Station helps Duplicants breathe in flooded areas.
• A survivor Duplicant, Minnow, can be recruited. Since the July 7, 2026 update, Minnow's Freediver trait gives +4 to all attributes while swimming.
• The Scramble DLC tool mixes content from several DLCs into a new game.

Common Mistakes to Avoid

• Digging into big caverns early. Gas floods your base and pressure drops.
• Farms next to hot machines. Crops die when temperature rises.
• No Wash Basins by the toilets. Food poisoning spreads fast.
• Running out of algae or dirt. Plan the Electrolyzer and farm transition before those stocks deplete.
• Too many Duplicants too soon. Each one needs oxygen, food, and a bed. Grow slowly.
• Overloaded circuits. Burnt wires waste materials and cause blackouts.
• Ignoring expectations. Learning skills raises morale needs. Balance skills with rooms and food.

Advanced Tips

• Automation (Automation overlay): Atmo Sensors, Thermo Sensors, Smart Batteries, and Liquid Level Sensors make machines run only when needed.
• Airlocks with liquid (Liquid Lock) separate gases without doors.
• Tame geysers by insulating them and piping their output. Steam vents plus Steam Turbines give free power.
• Exosuits let Duplicants work in dangerous areas without breathing the local gas.
• Plan heat sinks early. A cold biome or an ice-based cooling loop buys time before your Aquatuner build.
• Spaced Out!: Establish a second planetoid with teleporters or rockets, and ship resources on Rocket Interior modules.

FAQ

Which DLC should I buy first? Spaced Out! is the big expansion. The Planet Packs are smaller themed additions ($9.99 for Aquatic), and the Scramble DLC tool lets you mix them.

Which starting asteroid is best for beginners? Terra (base game) or the standard Spaced Out! starter clusters. Avoid Marinea and other flooded or harsh starts on your first colony.

Why is my base getting hot? Machines, electrolyzers, and generators all produce heat. Insulate machine rooms and move heat out with Aquatuners and Steam Turbines.

How many Duplicants should I have? Start with three and grow slowly, only when you have spare food, oxygen, and beds.

Can Duplicants swim now? Yes, in The Aquatic Planet Pack. Swimming skills unlock underwater movement, and there's a CPR mechanic.

My Duplicants are always stressed. What do I do? Add proper rooms, cook better food, raise decor, schedule downtime, and avoid giving everyone too many skills too fast.

Sources

• Oxygen Not Included Wiki (wiki.gg)
• ONI Wiki: The Aquatic Planet Pack
• Steam news: The Aquatic Planet Pack launch and updates 737790, 740622, 744825