Sadly I don't know anything about them personally - my LFS is rather small (though they really know their stuff) and never carry anything as odd as that.
Everybody has taken their best odd balls in this ugliness contest, and some other want to play poker.
However, the ugliest looking fish I've seen is this:
I could keep a horn nosed boxfish in my tank (provided It's behind a courtain, lights turned off and I'm wearing a blindfold) but never would keep a celestial goldfish.
Anyone find a good picture of hagfish or lamprey? Those are UGLY and NASTY (the hagfish eats rotting meat and the lamprey is a blood sucking parasite).
I just remembered this one thanks to an old thread being brought back to life...
To me, the Black piranha is beautiful, but I'm not so sure in this picture lol
There are many big lakes here with old, old Carp breeding ponds nearby that have these kinds of carp. There are many ancient legends about them too. What looks like the two front eyes are actually their nostrils.