I thought it best to leave it to the experts to describe. This is a quote from the Reef Series CD-ROM.
"The upper head and body of the southern are sand-coloured [dark brown for the northern] and covered uniformly with large, irregular, white spots that are approximately of equal size in all areas (note: the spots of A. guttatus (northern stargazer) are smaller, not as bright, and vary in size from head to tail). The lower head and body are pale. The spinous portion of the dorsal fin (3-5 spines)[ 4-5 spines for the northern ] is black, while the soft portion is pale with 2 blackish areas. The caudal fin has 3 longitudinal blackish-brown stripes on a whitish background, but (unlike in A. guttatus) the central one does not extend onto the caudal peduncle. The anal fin has a blackish stripe along its length, the pectoral fins are dusky with black tips, and the pelvic fins have an elongate blackish spot [dusky spot for the northern] near the outer ends of the inner rays. The body is mostly scaled but the head, throat, and abdomen are not. There is a Y-shaped bony process on top of the head, extending back from between the eyes. The area between the forks of the Y is covered with skin and on each side of this Y there is an electric organ covered by a layer of skin. Between each eye and a branch of the Y there is a fringed groove that curves back around the eye and serves as the opening for the posterior nostril. The back end of this groove is much closer to the rear of the eye than to the rear of the electric organ."
The habitat and behavior of the fish are described as "A bottom-dwelling inshore species found on soft bottoms [sandy, silty, or rubbly bottoms for the northern] in primarily shallow waters but known to go as deep as 228 feet [depths from near the surface to 120 feet for the northern]. It wiggles its body partially into the bottom sediment and blends with the background while waiting for unsuspecting prey to come near. Because of the possibility of a painful electrical shock, physical contact with this fish should be avoided."
The abundance and distribution are said to be "from North Carolina down along the Atlantic and Gulf Coasts of the United States, and south along the Central and South American coasts to Santos, Brazil. [For the northern, the range is only along the coast from southeast Florida to New York.] Both are labeled as 'uncommon.'
Photograph(s) used by permission of ReefNet Software from their excellent Fishes of the Caribbean and Adjacent Waters fish ID CD-ROM. Photo credit: both photos - ęDavid B. Snyder.