Pygmy seahorse

How do you identify a pygmy seahorse?

Bargibant's pygmy seahorse is one of the smallest seahorses known: 2.4 centimeters at most from head to tail tip, about the size of a fingernail. The snout is short, the eyes bulge, and the body is covered in bulbous growths that copy exactly the polyps of the sea fan it lives on; the prehensile tail stays wrapped around a branch. It comes in two color forms that follow the host: a gray-white body with red patterns and tubercles on red sea fans, a whitish body with yellow tubercles on yellow sea fans. To the naked eye it is impossible to tell apart from its perch. You spot it by the outline of its head in profile, and by the slight movement it makes to turn away from your light. Other pygmy seahorses, such as Hippocampus denise and Hippocampus pontohi, live in the same waters: Bargibant's is the stockiest and the only one with these large tubercles.

How does the pygmy seahorse live?

It spends its whole life on a single sea fan, Muricella plectana or Muricella paraplectana, between 16 and 40 meters deep, in the tropical waters of the central Indo-Pacific, from Indonesia and the Philippines to southern Japan, Australia and New Caledonia. It feeds on small crustaceans, drifting fish eggs and other plankton that it sucks in as they pass. As in all seahorses, the male carries the eggs: the female lays them in his brood pouch, whose walls are laced with capillaries that feed the embryos like a placenta, and the young come out fully formed and independent from birth. Several individuals, often a pair or a small group, share the same sea fan.

Where and when can you see pygmy seahorses in Indonesia?

It is there all year, wherever Muricella sea fans grow below 16 meters. In Raja Ampat, look on the sea fans of the Cape Kri slope and the top of Blue Magic, and on the walls of Magic Mountain in Misool. In North Sulawesi, it lives on the Lekuan walls of Bunaken and on the sea fans of the Lembeh Strait, at Nudi Retreat in particular. In Bali, it lives on the sea fans of the Liberty wreck's hull, between 12 and 25 meters. You won't find it on your own: guides know every inhabited sea fan and point the animal out with a stick, from a distance, so that everyone can spot it. A prescription mask or a small magnifying glass helps, and you stay just long enough for a photo or two before making room for the next diver.

Is the pygmy seahorse endangered?

The pygmy seahorse was discovered by chance: diver Georges Bargibant, who was collecting sea fans for the Nouméa aquarium in New Caledonia, found some clinging to a branch. René Catala, the aquarium's founder, proposed naming the species after him, and it was described in 1970. It has since been found throughout the Coral Triangle, but it is so discreet that its populations remain unknown: the IUCN lists it as Data Deficient, and CITES lists it, like all seahorses, in its Appendix II, which regulates trade. Its only real threat is the loss of its sea fans, to anchors, fins or trawl nets.