Bloat is a porcupine pufferfish who lives in Philip Sherman's office tank. When he gets scared or agitated, he bloats up, and then one of the other fish has to deflate him. He likes to be as disgusting as possible.
In the ending of the film, Bloat and the rest of the Tank Gang escape the aquarium exactly as Gill had planned, but Bloat then asks, "Now what?" ending the gang's joy of escape and causing them to worry about how they will get out of their plastic bags.
However, during the credits, the tank fish have escaped their bags somehow. As the credits continue to roll, Bloat is seen having a brief dispute with Gurgle. He then bloats up, and Gill and Gurgle start spiking Bloat around like a volleyball.
- Like all pufferfish, Bloat sucks water into a compartment in his stomach to inflate, and also like many pufferfish in real life, Bloat often has trouble deflating.
- Bloat doesn't have the chameleon-like eyes and color-changing abilities that real pufferfish do.