My Geophagus Brazilian(mother of pearl ) is a bit of a bully

[electrocutioner]

He keeps nipping the fins of a smaller member of his species,and constantly aggravating and chasing it around.Poor thing!
He doesn't seem to mind his other tankmates though.
3 yoyos
1 rubber nose pleco
3 tiger snails
1 vampire shrimp (tried a couple dozen ghosts and some other kind o shrimp,big bully acted like a fat man at the chinese buffet)
2 rams
2 beta sharks(tri-color)

I know my tank is pretty near fully populated(29 gal),but I'm thinking I might be able to put in 1 or two more.Any suggestions on a particularily colorful or exotic breed that my resident aggressor won't likely feel intent on terrorizing?

Heres a picture of the species in question.A cichlid,I beleive.

 

[electrocutioner]

Any Body?

 

[mr86mister]

well it seems, he already has his terrirtory established and adding a new fish might be the end for that new fish....but a good way to confuse him is, when you add new fish...turn off the lights and change the decor around(if you really feel the need), i'm not too familiar with this fish so i am not sure what would go with it.....anyone have any ideas?