In 2002 and 2006, we conducted a survey of historical collection localities for Enneacanthus chaetodon (Blackbanded Sunfish) in Maryland. Blackbanded Sunfish were detected at only one of six historical localities. This locality consisted of 17 quarry ponds, but the Blackbanded Sunfish was collected in only three of these. These ponds were characterized by low pH (<4.9), dense submerged and overhanging vegetation, and the absence or low abundance of non-native piscivores. The acidic nature of these ponds may provide refuge from predation for Blackbanded Sunfish by limiting numbers of non-native piscivores such as Micropterus salmoides (Largemouth Bass) and Pomoxis nigromaculatus (Black Crappie). As a result of the surveys described herein, the Blackbanded Sunfish state status in Maryland was elevated from Threatened to Endangered.