Deep Colors: Masked Butterflyfish Pair in the Red Sea

Masked Butterflyfish (Chaetodon semilarvatus)
Masked Butterflyfish (Chaetodon semilarvatus) in the Red Sea

by B. N. Sullivan

The Masked Butterflyfish (Chaetodon semilarvatus) is one of just a few species in the family Chaetodontidae that mates for the long term, thus they are most often seen in pairs.  They live in the Red Sea and the Gulf of Aden.

These are brilliantly colored fishes with bright yellow, vertically lined bodies.  They have a distinctive grayish blue eye mask,  the feature for which they are named.  "Semilarvatus" in Latin means "Half-mask."  The species has several other common names, including the Blue-cheek Butterflyfish and the Golden Butterflyfish.

I photographed this pair against a backdrop of colorful Nephtheid soft corals in the Red Sea.  Each fish was approximately 18 cm (7 in) long.

Hermit Crab with Bright Blue Eyes

by B. N. Sullivan

This is the White Speckled Hermit Crab (Paguristes punticeps), a Caribbean species of the Diogenidae family.  Adults of this species grow to a length of  3 to 5 inches (about 8 to 13 cm).  These reef dwellers inhabit empty gastropod shells, tail end first, so you won't normally get to see the crab's full length.

Without the artificial light produced by the camera strobe, these crabs look dark brown with white speckles.  It's also difficult to make out those wonderful bright blue eyes without artificial light and a macro lens.  But that's why macro photography was invented, right?

Jeepers, creepers -- where'd he get those peepers?!

One of the most noticeable morphological features of this species: both of its claws (chelipeds)  are approximately equal in size.  More commonly, the claws of hermit crab species are of different sizes -- typically the left claw is larger than the right.

All of the images on this page are of the same individual, photographed during a night dive at a site known as Cumber's Caves on the north shore of Little Cayman island.