Macro
The small things: nudibranchs, anemone shrimp, a clam that seems to flash, and mandarinfish at sunset, with where to look for them.
Background photo: Megan Applegate (Palau)
Sea slugs
3 species, all photographed in Palau
A dorid nudibranch at least 50 mm long, from the tropical western Pacific (Wikipedia).
Key marks: A white body under a broad yellow outer mantle, separated from the light-brown centre by a wavy white-and-black line; the mantle edge is brown with a thin purple rim. Gills and rhinophores vary from translucent white to light brown (Wikipedia).
At Palau: Feeds on sponges (Wikipedia). Photographed in Palau in January 2023.
Invertebrates
Look in the anemones and the cracks
A tiny shrimp, up to 2.5 cm, of the western Pacific, at 2–40 m. Also listed as Periclimenes sarasvati (Reef Guide).
At Palau: Photographed among the tentacles of an anemone. Photographed in Palau in January 2023.
A file clam whose mantle edge seems to flash like a strobe. The light is not its own: a strip of highly reflective tissue packed with silica nanospheres alternates with red tissue and reflects daylight or a dive light. The flashing most likely evolved to deter predators (Wikipedia).
At Palau: Its range runs from Indonesia to the Palau Islands and New Caledonia (Wikipedia). Photographed in Palau in January 2023.
Giant clams
Palau has seven of the world’s nine kinds of giant clam (Pew 2015); German Channel is one place divers report them (Dive The World).
Small fish
Mandarinfish, gobies and shrimpfish
A dragonet only about 6 cm long. It has slime instead of scales, which may protect it from disease and deter predators; its bright colours may be a warning (Wikipedia).
Key marks: A bright blue body with swirling orange stripes, a blue-green face with bold blue stripes and usually red eyes; males have a very tall dorsal fin (Wikipedia).
At Palau: Mandarin Fish Lake, a calm, shallow inner-lagoon site, is known for mandarinfish at sunset (Palau Dive Adventures). Photographed in Palau in January 2023.
A goby up to 7.5 cm long that lives on sand and silt in lagoons and bays, near rubble, coral or leaf litter, at 1–30 m (Wikipedia).
At Palau: Photographed in Palau in January 2023.
A razor-thin fish up to about 15 cm long that moves in synchronised groups, head down (Wikipedia).
Key marks: Hangs head-down among the spines of Diadema sea urchins or in staghorn coral, and darts to them when threatened (Wikipedia).
At Palau: Photographed in Palau in January 2023.
Where
Sites dive reports mention for small animals
A calm, shallow inner-lagoon dive for mandarinfish at sunset (Palau Dive Adventures).
Besides the mantas: garden eels, mantis shrimp, jawfish, shrimpgobies, cuttlefish, nudibranchs and giant clams; night dives bring out different animals (Dive The World).
A wall with lionfish, stonefish, leaffish and nudibranchs among soft and leather corals (Dive The World).
Wrecks with lionfish, glassfish and macro critters (Palau Dive Adventures).
A cave with an air pocket and shrimp (Palau Dive Adventures); an overhead environment, for trained divers only (PADI).