New Additions To A Fully Grown Severum

[ZoddyZod]

I've got a well established (loosely) South American community tank (300L) and I'm looking for potential SA cichlid additions. Previously I had 6 angels and an orange Sev that was introduced when small. He/she is now a good 7-8 inches and I only have 2 angels remaining. Complete stock is below.
 
I'd like to add another medium to Sev size cichlid but I'm wary about adding any to the tank which the Sev now 'owns'. I've thought about the following - any watchouts or other suggestions?
 
Blue acara
More angels
Thorichthys ellioti
Pearl Cichlid
 
other inhabitants are..
 
Bronze corys, rummynose tetra, 3 Bolivian Rams

 

[RobRocksFishTank]

Adding new angels might be difficult unless the new ones outnumber the ones you have.
 
Have you considered adding more than one of the other cichlids to spread out any possible aggression from the severum?

 

[blueacara]

hey i would say imo put in a few blue acaras 2-3 and maybe another sev just remember when i had cichlids a while ago when i introduce new fish i always rearranged the decor or rock and there were almost no aggression 

 

[snowflake311]

A Cichlid that has been ruler of the tank for a year or more is no longer fooled by the tank rearranging.  What I have found to be the best way to add more Cichlids of any kind is get young ones. Make sure the ones you are getting at about half the size or even smaller than half the size of the biggest fish. 
 
If you want to add Angel fish it is easy if you add in some that are the size of a quarter or silver dollar not bigger. 
 
Adults tend to be more excepting of younger less experienced fish.