there is an implied verb at the end:
No one likes tropical fish more than [does].
So it is clearly "she" and not "her".
This brings up a common mistake. Many people say
My mom likes cookies more than me.
meaning that mom is very fond of cookies. But what they are saying is that
My mom likes cookies more than [she likes] me.
which is probably not the case. To be correct, they should say
My mom likes cookies more than I [do].
No one likes tropical fish more than (she, her).
I can't really tell because usually I separate the sentence into two but the word is at the end so I can't.
2 answers
ITS SHE I GOT IT WRONG