The masked angelfish, Genicanthus personatus, is an idolized reef fish which is as beautiful as it is expensive and rarely seen. The stunning marble white body coloration of the masked angelfish is accentuated by a perimeter of color that gives the masked angelfish a truly angelic appearance. Masked angelfish are endemic to Hawaii and they are most abundant in the Northwestern Hawaiian Islands where most commercial activity including the collection of aquarium fish is strictly prohibited.
No other groups of reef fish has captivated the aquarium hobby like the colorful and varied angelfish. G. personatus grows to a maximum length of eight inches but the caudal fin filaments of a mature male can be several inches long as well. The fully grown masked angelfish does not have any wild or crazy coloration and it barely sports any markings at all. The masked angelfish is a predominantly white fish. The white coloration of the masked angelfish is a not at all a pale white, but a brilliant white which gives it a stunning appearance at all stages of its life cycle. As a juvenile the tiny white masked angelfish has a small black patch over its face, eyes and mouth included. Adolescent masked angelfish eventually develop a mostly black tail and the black facial mask becomes punctuated with blueish white lips.
Masked angelfish are protogynous hermaphrodites (they start out life as a female and eventually turn into males) and they are sexually dichromatic (a separate coloration for males and females). A fully grown female masked angelfish has an all white body color, retaining the mostly black tail, yellow pelvic fins and the black mask becomes reduced in size. The amount of black on the female masked angelfish shrinks to a small black patch which may encircle the eyes, with a little black under the lips and a black edging to the gill cover and gill spine.
At about six to seven inches long a female masked angelfish will to male sex and male coloration. The male masked angelfish also retains the black tail fin but its pectoral fins, its entire face and the edge of its dorsal, anal and pelvic fins become a bright yellow orange color. As an added bonus, like other members of the Genicanthus genus the male masked angelfish also develops long streamers to its caudal fin. On rare occasions, the male masked angelfish will temporarily display an overall grey body coloration which is used to signal cleaner fish and shrimp that it is safe to approach for removing parasites and little bits of dead tissue.
The masked angelfish can be reliably sighted at over 300 feet deep in Kauai and it occurs progressively shallower as you go west to the Northwestern Hawaiian Islands. At the extreme end of this range is Pearle and Hermes reed where the masked angelfish can be frequently spotted in less than 100 feet of water. The fact that masked angelfish occurs deeper at more southerly locations is an indication of its preference for cooler water.
In early 2009, a pair of masked angelfish made their way to B-box aquarium in Japan and they were sold to rate fish collector in Hong Kong for $30,000. Because of its price, color and limited availability, the masked angelfish is truly a perfect storm for a highly desirable reef aquarium fish.