For that warm most cichlids will do good. Maybe look into an Amazon one to ensure it tolerates the temp well.
Chocolate cichlid would be very good in warm water like that and is very colorful.
20 inches wide or 20 inches high?
By chocolate I mean hypselecara temporalis, rather than the typical uaru. Still stocky but able to keep dithers with it.
If you want something more slender I would go for a Jack (pair?) or RTM.