Do they have leafy sea dragons at national aquarium in Baltimore?

No, the leafy seadragon is found only in southern Australian waters, from Kangaroo Island at the eastern end of its range, westward to Jurien Bay, 220 km (140 mi) north of Perth. It was once thought that individuals had very restricted ranges; however, further research has discovered that seadragons will actually travel several hundred metres from their habitual locations, returning to the same spot using a strong sense of direction. They are mostly found over sand patches in waters up to 50 metres (164 feet) deep, around kelp-covered rocks and clumps of sea grass. They are commonly sighted by Scuba divers near Adelaide, especially at Rapid Bay and Edithburgh.