I am looking for a single medium-sized cichlid (~adult angelfish size) that would "fit" in a 300 L tank with 16 loaches without turning the aquarium into a war-zone.
Background: Right now I have 3 angelfish in the tank which used to get along with the loches and the high current quite nicely. This changed when I added 5 kubotais. They are very inquisitive (much more than my clown or zebra loaches) and are harrassing the angelfish almost constantly. I am planning to give them away into good hands so they can live in peace again.
I really do like cichlids though and would love to add a solitary (or pair, if necessary) to the tank again. I know that pretty much all the Malawi cichlids are out of the question .. so, what is left?
I obviously need a species which is a bit more self-confident than angelfish are .. while not being a bloodthirsty serial killer.

Marcos from Brazil has Jack Dempseys with his loaches, but I'm not sure if I am brave enough to try this, given their usual reputation. Maybe you can comment on this, Marcos?
Any suggestions are welcome!
-Connor
PS: Almost forgot: pH ~7.2, 7-10° dGH, 6° KH