The authors have made close observations of A. macneilli at One Tree Island and at various places on the northern Great Barrier Reef between Green Island and Lizard Island. The species dwells in caves, crevices, and under ledges, always in areas of subdued light at depths ranging from about two to three metres to at least 15 metres. It commonly forms aggregations which may include more than 100 individuals. The fish are frequently seen swimming upside down near the roof of the cavern, apparently orienting dorsally to the lighter bottom which is often composed of sand or fine silt.
The gut contents of eight specimens of A. macneilli and A. flavissimuscollected in the same cave at Spur Reef, off Port Douglas, Queensland contained primarily copepods, ostracods, and amphipods.