A school of yellowmask — also known as 'elongate' — surgeonfish (Acanthurus mata) swims beyond the slopes of a seamount. Particularly interesting is that the school consists of both dark and light-colored fish; most photographs that I have seen were of the light-colored morph or phase, though these fish are probably capable (as are many others) of changing coloration within seconds. (Planet Rock, Madang)
A yellowfin surgeonfish (A. xanthopterus) swims through blue water, far from the immediate safety of the seamount. Large schools of this species and other surgeons and unicornfishes were typical of the near-reef water-column species that you'd see if you swam a short distance away from a seamount. (Inglis Shoal, Kimbe Bay)
A bluelined surgeonfish (A. lineatus) scoots quickly across a gently-sloping part of the reef between the miniwall hard up against the shoreline and the nearby vertical drop-off that plunges to extreme depths. (Hole in the Wall, Northeast coast)
A bluelined surgeonfish streaks rapidly across the top of an oceanic reef. I've always found these spectacularly-patterned surgeonfishes hard to get a good picture of because they tend to be so flighty and I most often encounter them in very shallow water where, even without wave action and surge and with or without SCUBA gear, it can be very difficult to handle a camera. Most that I've seen tend to occur in water about one meter deep, right on the edge of the shore or on top of very shallow reefs further out to sea. (May Reef, Kimbe Bay)
A Vlaming's unicornfish (Naso vlamingii) on the side of a seamount. Unicornfishes are part of the surgeonfish family (family Acanthuridae) and share the familial trait of having scalpel-like spines in the area just forward of the tail, an area called the caudal peduncle. This spectacularly-colored species is large (up to 55 cm length) and feeds on zooplankton near outer reefs and similar habitats. Vlaming's unicornfish often occur in great concentration at the upcurrent end of such reefs and I have seen them active at night during some of my night dives on PNG seamounts. (Planet Rock, Madang)
Vlaming's unicornfish...being cleaned by a wrasse on the edge of a seamount. (Planet Rock, Madang)