Oxygen Algae (氧气藻; pinyin: yǎngqì zǎo) was a plant and an environment modifier in Plants vs. Zombies Online, Plants vs. Zombies: Journey to the West, and later Plants vs. Zombies: Great Wall Edition. It is an aquatic plant, and as such can only be planted underwater. Since most plants cannot be planted underwater, the Oxygen Algae must be used. When planted, the player will be able to plant any other plant in a 3x3 area around it in Plants vs. Zombies: Journey to the West, or a cross-shaped area but can also upgrade the oxygen range by spending sun on it in Plants vs. Zombies Online.
Its Plants vs. Zombies Online appearance could additionally be based on the bubble algae (Valonia ventricosa), a species of green algae found in many oceans throughout the world in tropical and subtropical regions and is one of the largest unicellular organisms on earth.
In Plants vs. Zombies: Journey to the West, Oxygen Algae was the first plant obtained in the Underwater World. It was integral to the waterlogged areas of Underwater World and The Dragon's Palace as it provided oxygen in a 3x3 area around itself, allowing non-aquatic plants to survive underwater to fight various undersea zombies.
It was later added to Plants vs. Zombies: Great Wall Edition, as Journey to the West had been merged with the game before the app was removed.
In Plants vs. Zombies Online, Oxygen Algae released oxygen in a cross shape around it to let land plants survive in an aquatic environment. It also had a meter below it with 3 sections, which was used to show the level of Oxygen Algae. The player could click on the Oxygen Algae to level it up by spending some sun.
- The first level costed 75 sun and made the oxygen-supplying range become 3x3.
- The second level costed 125 sun and made the oxygen-supplying range become a diamond shape.
- The third level costed 200 sun and made the oxygen-supplying range become 5x5.
Plants vs. Zombies: Great Wall Edition/Journey to the West
Oxygen Algae can provide oxygen bubbles to plants on land
Range: Cross-shaped (3x3 in-game)
Must be planted underwater
"Oh...hey..." Like a puffy air bubble, it wasn't that he was willing to vomit, only to blame him for drinking too much soda last night. However, there are rumors that he will not do anything other than spit.
Plant Food effect
- Algae is actually neither plant, animal, nor fungi. Algae is usually a single-celled organism, however, multi-cellular algae are not unknown to exist.
Specific to Plants vs. Zombies: Great Wall Edition/Journey to the West
- If it got eaten, the player had 5 seconds to plant another Oxygen Algae before all plants in the 3x3 area where it once was drowned.
Specific to Plants vs. Zombies Online
- It was the first plant in Plants vs. Zombies Online to be upgradable during the level without the help of a seed packet.
- Ironically, it could not be upgraded from the Greenhouse.