20,000 Fish Under the Sea

The genus Virgularia consists of 22 species, some of the many coral species  known as sea pens. Aronnax identified "an admirable genus Virgularia from Norwegian waters" in the Nautilus's salon (20,000 Leagues p. 74). He presumably recognized one of the three species in Vigularia identified before he boarded the Nautilus in 1866. Pictured is Virgularia mirabilis, the slender sea pen, which can indeed be found in Norwegian waters (along with the rest of the Atlantic). 

The mullet Aronnax described seeing in the Western Pacific, "some bewhiskered mullet, marked with a double line of black" (20,000 Leagues p. 98) does not seem to match any known species of mullet. While multiple species of mullet do live in the area, none that I found have barbels (sensory strands, appearing similar to whiskers, on the chins of fish); while multiple species of mullet have barbels, none that I found are native to the west Pacific or have two black stripes. Pictured is the striped red mullet, a colorful fish found in the Mediterranean Sea, northern Atlantic Ocean, and Black Sea.

Sea pen coral, among the specimens Aronnax notes in the Nautilus' salon, is soft coral in one of the 16 families of the order Pennatulacea. Although its common name comes from its resemblance to a quill pen, most sea pens do not have the feathery appearance that inspired the name. Pictured is one that does: the slender sea pen (Stylatula elongata).

There are three species of fish commonly known as the "green wrasse" (20,000 Leagues p. 98); the passengers of the Nautilus, then traveling off the coast of Japan, could only have seen Choerodon schoenleinii. Choerodon schoenleinii, also known as the blackspot tuskfish or Tsing Yi (青衣), is easily identified by the single black spot on its dorsal fin. In 2011, a diver photographed a green wrasse smashing a clam on a rock, the first images of a fish in the wild using a tool.

Another specimen in Nemo's cases is "isis coral from the Molucca Islands" (20,000 Leagues p. 74). The genus Isis contains one species, Isis hippuris; along with many other coral species, its common name is the sea fan. A steroid isolated from the coral has recently appeared in the scientific literature as a possible treatment for cancer.

Pictured is seemingly the only existing image of Dasyatis sinensis: the illustration accompanying the original description of the species.

Aronnax identifies "some gorgonian coral arranged like a fan" (20,000 Leagues p. 74) among Nemo's specimens. He is presumably referring to some type of sea fan, soft coral in the order Alcyonacea (also known as sea whips). Alcyonacea found in shallower water, with stronger currents, are more flexible and look more like fans; the photograph shows a Venus fan (Gorgonia flabellum).

The name "Chinese triggerfish" seems only to appear in translations of 20,000 Leagues Under the Sea. What fish, then, did the travelers see? Luckily, Conseil identifies the genus, and Balistes only has eight species. Only one, Balistes rotundatus, is found in the West Pacific, where the Nautilus was traveling. My usual reference sources provide neither information, a common name, nor a photograph, so this post is illustrated with Balistes capriscus, the grey triggerfish. This triggerfish displays the coloring Aronnax describes (grey on top, white on the bottom), but it's only found in the eastern Atlantic.

Organ-pipe coral, displayed in Captain Nemo's salon on the Nautilus, is notable for its bright red coloration and the "pipes" for which it was named. The coral's red skeleton is not visible while it is alive, as it is covered in grey polyps.

When asked for an opinion on the "monster" which has been sinking ships in 1866, Professor Aronnax theorizes that it is a narwhal--one larger, faster, and stronger than any found before or since. Of course, his theory is off-base, and the narwhal does not actually appear in the novel.