@Great Argus this is Acanthochromis polyacanthus (northern Great Barrier Reef form). The colour pattern does resemble some species of Pycnochromis (recently recognised as a distinct genus from Chromis), but is significantly larger and differs in body shape.
@DaLilFishie I thought it seemed a bit large - I was unaware of this color form of the Spiny Chromis, although it seems quite well documented from searching. Very interesting, thanks for the information.
