Well the one with the missing lower jaw did eat though, so I do have some hope for him.  He is MIA again as of last night.  I have no idea where he is hiding, but he has a good hidey hole that's for sure!!  I hope this means that the 4th one is also just hiding real well.  I know all 4 ate about 3 days ago, plus at the LFS before being sent 7 days ago, so the missing two aren't in any risk of starving at this point.
There is definitely a boss Jawfish.  He is the biggest one that has the biggest hole.  He was sharing with the 2nd one, but he kicked the second one out yesterday.  Spousal warfare I think!  
