Planet Zoo 2 Aquariums: How to Build, Fill and Heat One

How to build an aquarium in Planet Zoo 2

Aquariums are a habitat type of their own, new in Planet Zoo 2, and the only home for its 37 fully aquatic animals. Building one works like a land habitat: open the Habitat Barrier tool, choose Aquarium and draw the walls with the Line or Curve tool, setting their size, direction and height. The difference comes with the gate. As soon as you add an Aquarium Staff Gate, the space fills with water. Join that gate to your paths: Keepers dive in through it, which is also why it can sit high on the wall. Ready-made aquarium blueprints, from the game and the Workshop, skip the drawing.

Aquarium not filling with water

The water only comes once the tank has an Aquarium Staff Gate. If yours stays dry, check that the walls were drawn with the Aquarium tools rather than a land habitat barrier, and that the gate is an Aquarium Staff Gate. To change the walls of a finished aquarium, the water and animals have to come out first: box the animals, press Drain Water under the Info Panel, edit the barrier, then add the water back.

Salt water, brackish water and filtration

New aquarium water is Freshwater. Its salinity comes from the filtration network it is piped to: build a Water Filter inside the radius of a power source, pipe it to the node on the Aquarium Staff Gate with Edit Filtration Network, and set the network to Freshwater, Brackish or Saltwater. A saltwater animal cannot survive in fresh water, and one network has one salinity, so tanks with different water need different networks. Each animal's water type is on our Planet Zoo 2 aquatic animals list, and the Planet Zoo 2 water filtration guide covers the network in detail.

One Water Filter cleans up to 500 m² of water. The Great Hammerhead alone needs 960 m² of deep water for one adult on its Zoopedia panel, so its tank needs two filters from the start. A crowded tank needs more again: the aquarium's filtration demand grows with its water and its animals, and when the network's Filtration Rate falls short, Water Cleanliness drops.

How to heat an aquarium or change its temperature

Each aquarium animal has a water temperature range on its Zoopedia page, and welfare drops outside it. Power the Aquarium Staff Gate, then set the temperature in the Environment tab of the aquarium's Info Panel; the lighting is set there too. Since Update 1.0.8 an aquarium without power is clearly marked. Heating costs money: the bigger the gap between the set temperature and the weather, the higher the aquarium's running costs. To keep several species in one tank, the Planet Zoo 2 habitat planner finds the temperature and salinity they share.

Aquarium tunnels and viewing

Guests see more through a tunnel. Add a guest gate to the aquarium and you can build a tunnel through the water; tunnels can run at different heights in the same tank. The walls can use one-way glass or curve inwards and outwards, and aquariums can stack over several floors or sit underground. Invisible barriers and scenery make a more natural-looking tank.

Leaks, cleaning and disease

Aquarium barriers lose condition and start to crack. Mechanics service them; leave it too long and the tank leaks, guests near a leak run away, and an Inspector who spots one ends the inspection with a fine. Inside, Keepers clean the glass to restore Tank Cleanliness, which falls much faster when the water is dirty. Low Tank or Water Cleanliness becomes a disease risk, and sick aquarium animals need a Vet and a spell in quarantine: our Planet Zoo 2 quarantine guide shows what it needs. Update 1.0.8 on 29 October 2026 fixed disease spreading faster than it should in aquariums.