festivums , keyhole cichlids, blue and gold rams, keep silver dollars their south american just not cichlids.
How big is the severum , if small, angels can grow up toghether with them quite well. neither the acara or severum are that aggressive they will eat only what fits in their mouth. A firemouth will do well also. Rams may not work if severum is too big but will work if they grow toghether.
Presently my blue acara lives with 3 festivums 3 angels 1 firemouth 1 keyhole 2 blue rams 1 convict all raised toghether as small fish though (55 gallon 4 foot). Convicts can be nasty would not recommend this one.
I had 2 gold sevs with silver dollars , firemouths, and cons many years ago.