I agree with the others, it is one of the Geophagus braziliensus complex, of which there are at least half dozen species.
These can reach at least 12", and are a bit aggressive, especially if kept a warm tropical temps. As the name implies, they come from southern Brazil, Uruguay, and Argentina's are not strictly tropical, but more sub-tropical. Some have even been found in brackish water, so are very tolerant of varying water chemistry types
I have kept G braziliensus outside in ponds in Wisconsin in the summer, where they spawned and took temps down in the low 60sF.
I kept my G iporangensis in room temp tanks (unheated) where they also spawned at temps in the high 60sF.
Below are young iporangensis.
great fish to keep, although not a particularly good one for a community setting.