Juveniles of some reef fish species are much more colorful than their adult counterparts.  This is kind of counterintuitive—one would expect the vulnerable young to bear cryptic coloration to conceal themselves from potential predators.  The cryptic coloration strategy is employed by some reef fish species, but for others the colorful approach seems to work.

Juvenile Hawaiian hogfish, less than three inches long.  Not a common sight.

Last week I ran into two examples of colorful juveniles at (where else?) Mahukona.  The first was a Hawaiian hogfish in about twenty feet of water.  Full grown adults of these large wrasses are rare at snorkeling depths, but smaller adult females are fairly common.  Both the less common juveniles and the small adults are quite colorful, juveniles especially so—their bright yellow backs standing out from a considerable distance.

Small (about ten inches) adult female Hawaiian hogfish.  Colorful, but not as conspicuous as the juvenile.

The other colorful juvenile is the freckled hawkfish.  (Another common name for this fish is blackside hawkfish, but I like freckled because the freckles on this species are so distinctive.)  These are fairly common on Hawaiian reefs in summer and, like the juvenile hogfish, stand out from a distance with their vivid yellow backs.  The somewhat duller adults are common and conspicuous all year.

Juvenile freckled hawkfish

Adult freckled hawkfish

Hawkfish tend to perch motionless on the reef, waiting to ambush fish or invertebrate prey.  Their sedentary habits and relative lack of fear make them easy to photograph.  Below are the other species of hawkfish commonly seen at snorkeling depths in Hawaii.  Juveniles of these species look pretty much like the adults.

Stocky hawkfish, the largest of Hawaiian hawkfish—large enough to be occasionally targeted for human consumption. This is typical coloration.

An unusually pale stocky hawkfish. I don’t know if this individual is permanently pale or if it has temporarily adopted this coloration.

Arc-eye hawkfish. Hoover states that these are among the most common of Hawaiian reef fish. They are certainly very common on North Kohala reefs.

Another arc-eye

Redbarred hawkfish. These pretty fish are also very common, but are not as conspicuous as the other species because they tend to station themselves in more sheltered locations on the reef.