I have a 12 gallon crate (tiny indoor pond?) with a female paradisefish and a trio of dwarf bumblebee cats. The paradisefish ignores the bumblebee cats entirely... havent seen any aggression at all from one to the other.
One day I was at Petland and shaw that they had a single baby albino bronze cory in their cichlid tank. I bought him out of sympathy, figuring he could live out a decent existence in the crate tank, figured all the tankmates would continue to be civil.
As it turned out, the paradisefish freaking hated the little cory, and really kicked his butt. A few days after I put him in the tank I noticed he wasnt visible, so I looked under the decor to find him all torn up hiding under a piece of driftwood.
Needless to say he's in his own tank now. Actually doing quite well... active, eating like a pig, growing, mostly healed up, except for a missing eye. Poor little guy, what a trooper.