My salvinis are pretty outgoing, sizes 1.5" (female) and 2.5" (two males)... they're the only cichlid in the tank that comes to the surface for food... they even nibble on floating pellets (hikari bio-gold+) that were going to waste because my other cichlids refuse to eat from the surface, but the tank is very active and there is a lot of dither fish (loaches, eel, siamese algae eaters, prawns).
The way I understand it lonely fish tend to take way longer to feel comfortable in a new tank, because there's nothing else in there indicating it's "safe" to be out and about... that's the purpose of dither fish. At least my clown loaches are always the first ones to come for food, they get into the net and sit there for hours when I leave it in the tank lol, little pigs aren't afraid of anything... they even nibble on my fingers when I'm re-arranging the tank... that way the rest of the fish know it's safe and come out as well.