Pufferfish can appear inflated and deflated. Their deflated appearance depicts them as a small, cute, spherical green fish, with one fin on each side, two triangular ears, a smiling mouth, and a bumpy underbelly.
They become much much larger in their inflated appearance, being a green sphere with many spikes of varying sizes poking out all over. Visible in the middle of the inflated pufferfish are its eyes and mouth, but this time frowning. Nearby are its two ears and fins, which are hard to notice due to their spike-like appearance.
Pufferfish appear as they did in Aquanaut, only being different shades of green, robotic fins, and having an air plug.
Pufferfish are found stationary in levels, and are constantly inflating and deflating themselves every five seconds. They can be killed by the player with one hit from a bomb. If the Submarine comes in contact with them, however, the player will lose one segment of health. Pufferfish are often encountered near small gaps, where their inflation makes the gap temporarily impassable.
Pufferfish act exactly as they do in Aquanaut, only they inflate more often. They are placed near metal bars, where inflating can temporarily block it. Pufferfish are only found in water segments of the level.
- The pufferfish resembles the character Bloat from Pixar's Finding Nemo.