The Pacific Fat Sleeper, Dormitator latifrons, is a member of the Sleeper or Eleotridae Family, and is known in Mexico as puyeki. environments over sandy and muddy substrates, such as estuaries, stagnant ditches, and low current velocity coastal creeks. They are extremely tolerant of dramatic changes in salinity even up to 50%. They are very hardy and capable of surviving for up to 10 hours out of water due to their ability to absorb oxygen through their broad and highly vascularized forehead.