We conducted multiple surveys to determine the distribution of the non-native Herichthys cyanoguttatus (Rio Grande Cichlid) in the Greater New Orleans Metropolitan Area (GNOMA). First, in 2003–2004, we trapped H. cyanoguttatus in Lake Pontchartrain (an oligohaline estuary) to determine if this freshwater species occurred in estuarine habitats. Our goal was to test the prediction that H. cyanoguttatus used estuarine corridors to disperse. Second, we sampled and compared 16 GNOMA sites before and after the 2005 hurricanes to determine how H. cyanoguttatus populations responded. Finally, we monitored H. cyanoguttatus populations monthly over two years (2006–2007) at six sites within the GNOMA to determine if numbers continued to increase after the hurricanes. We confirmed that H. cyanoguttatus: 1) does occur in estuarine habitats (0 to 8 psu), 2) effectively survived the 2005 hurricanes, 3) has increased significantly from 2006 to 2007 at three of six GNOMA sites, 4) is currently found more often in urban sites, and 5) persisted through the atypically cold winter of 2009/2010.