These guys are cool. A little skittish, but once you get one comfortable with being close to them, they love to pose.
Oh, and it is entirely accurate to call these “guys” as they are all adult males. Ribbon eels change color and sex as they grow older. Juveniles are black with a yellow stripe along their back (it is the last photo here – sorry for the poor quality), while adult males replace the black with that bright blue and expand the yellow on their faces. Finally when they change sex to female, they change color to all yellow. Weird, huh?