Damselfish
(Family Pomacentridae)

These are small, drab territorial fishes that are common in most shallow habitats. They have one nostril instead of the usual two. A few are brightly colored. These include the Clownfish or Anemone fish and the famous, aggressive Sergeant Major. The male Sergeant religiously guards the fertilized eggs that cover the rocks like a purple carpet. He will chase all comers away. The other fishes have to swarm down to feed on them, making further defense futile.

Some damselfishes are social and others are solitary. Some feed on plankton, schooling above the reef in the water column. Others are solitary and very territorial in areas where alga; growth is heaviest. This is one of the largest fish families with about 350 species, 14 of which are found in Hawaii.

Blue-eye Damselfish
(Plectroglyphidodon johnstonianus)

This fish is also known as the Johnston Island Damselfish. It is yellow-gray with bright blue eyes. Its dorsal and anal fins have blue margins. Its rear is sometimes darker than the front. It feeds partly on coral polyps and is found in deeper water. I have always found them in live coral. They are either very territorial or very curious. This one kept getting in the way of the Harlequin Shrimps that are also in the photo.

Humbug Damselfish
(Dascyllus albisella)

The Humbug is also known as the Hawaiian Domino Damselfish, the Hawaiian Dascyllus or the Onespot Damselfish. Juveniles are black with a light white spot on each side and a neon-blue white spot on the forehead. This spot is lost as adults where they become black in front and back and grayish white in between. They can lighten or darken their color and become almost white when spawning.

They are always found in around branching coral heads, and if quiet on approach one can always hear their little chirping sounds. They are found at 20 to 60 feet or more. You will often find them at depth swarming around a solitary coral head. They are sometimes aggressive either alone or in groups as are most damselfish.