Nibbles are Chain Chomp-like fish that appear in Paper Mario: The Thousand-Year Door. This fish appear to attack Mario but Mario cannot engage them in combat. These enemies appear only in water areas of the game, inside of rivers, ponds, the ocean, and even swimming pools.
Whenever Mario falls into the water, a Nibbles attacks him, dealing one point of HP worth of damage. Like most overworld obstacles that deal damage, Mario cannot die from a Nibbles. In addition, Nibbles do not attack Mario if he is in his sailboat form.