Balloon Fish resemble pufferfish due to their round appearance and ability to expand. Shooting these balloons with ink will inflate the balloon and eventually pop it, spreading large amounts of ink over a wide radius. The ink that shoots out of one Balloon Fish will inflate and pop any other Balloon Fish nearby; this chain reaction can result in a massive area being covered in ink. Balloon Fish are often found on tall walls that are hard to climb, or around groups of Octarians, to make progress through the levels easier.