ButlerKoferri(sp)

I've had my tank for about 6 months..

55 Gal.
Had 5 Convicts, A blue acura, and A dempsey.
Bought some fire mouths and a dragon fish..
All devoured by the convicts.. Mind you these are small and medium
convicts..
Went to the local fish place, talked to a very cute, but not to bright
college girl who worked there. I saw a large striped fish in the
"agressive" section, and asked about it and how well it would "get
along" with the other fish.
She assured me it would be just fine..

This fish is the devil.!

It has since ate 3 convicts.. digs up all the plants. mauled the Blue
acura, and an algea eater(they have been moved to a new tank)
Tears the plastic plants apart, moves the gravel into big piles(thus his
name "bob" the builder)
and is always attacking him self in the mirrored backround. It also
plays kick ball with the skull and crossbones ceramic piece as well.

I put a divider wall in and this fish either jumps over, or when I raise
it to the cover, digs under the wall. I think this fish was Steve
McQueen in its past life.

The Jack demsey and remaining convicts have since bunkered down in the
volcanic rocks and ceramic caves... and come out only to feed , and then
they are under attack.

My questions a

1)is this normal behavior?
2)Do they make Fish Prozac?
3)What can I do to stop this fish from destroying the inside on the
tank.

I like "bob" But another big tank is out of the question, wife would
drag me into divorce court(I have three tanks) He is about 6 inches
long and a great looking specimen. I saw one in the same store about
three weeks ago that was about 4 inches and a sign on the tank said
"19.95 or Best offer" so I think these fish are known for being a pain
in the butt.

ANY suggestions would be greatly appreciated.

Thanks in advance.