rigin:Brazil Rio Negro, Orinoco in Columbia, Venezuela, Peru Jurua Appearance:Aequidens diadema, also called the royal Acara (diadema = Greek for crown or crowned). This species was first described in 1840 by Heckel. Sex Aequidens "the real acara's" was recast in 1986 by Kullander. It can reach a length of about 25cm. Males are generally slightly larger and have more dots (stripes) pattern. Also, the men more color in the dorsal fin than the females.