What things have you succeeded with in your aquarium that was supposed to be a NO, NO?

[revhtree]

What things have you succeeded with in your aquarium that was supposed to be a NO, NO?

What fish, coral, equipment, etc.?

 

[Steelerfan747]

Keeping multiple tangs (4) in a 120g & keeping large # of fish (11) in a 46g. I am not recommending anyone to do this however.