Fish looks "happy"

[Moloch]

My (small) rubber lip pleco always looks like he's just been caught in the act.
My JD always seems like these thinking, "You talkin ta me?" or like everything is just a waste of his time.
My bichir always seems like he's just biding his time & plotting...

 

[knifegill]

My Oscar looks like he ate a strong mint.

 

[Noa]

My little flowerhorn always looks like he's about to cry because his bottom lip sticks out a little. Also he's a big wuss and is always hiding and peering out from around corners.