Aw, Fish-Eye! You're right, there doesn't seem to be much in the way of fanart for that particular set of characters...I think I've seenone of Fish-Eye in a sailor-suit, and that's about it.
I like the emotion here...he (Fish-Eye's male, right? I've only ever seen the dub, but I know they gender-swapped more than one character D:) seems sort of uncertain, but in a hopeful sort of way...or maybe a little shy. The way the hands are positioned, almost as if he's kneading them, and the eyes in particular convey a lot of emotion.
It might add a lot of depth if you added a little bit of shine tothe hair...nothing extreme, just a rounded stripe of lighter turquoise (maybe a shade or two darker than white).
I like the shadow the loose lock of hair casts on his face. ^_^
Aww! How pretty, I love the bright blue color, and she looks very pretty! Great job! ^_^