Fish Inside Out

Fish are vertebrates — animals with backbones — and have bodies supported by a bony skeleton. Variations in the skeleton, such as the number of vertebrae or the position of fins, are documented with X-rays. The Smithsonian’s National Collection of these Fish X-rays featured in the national collection were originally made for research purposes — allowing scientists to study the skeleton of a fish without dissecting or altering the specimen in any way. However, a representative of the Smithsonian explains that, “the striking images [also] demonstrate the natural union of science and art and a visual retelling of the evolution of fish.”

“X-ray Vision: Fish Inside Out,” is a traveling exhibit that showcases the inner workings of fish in these dramatic prints. Below, Mission Blue offers a look 5 of the images highlighted in the exhibit. In total, there are 40 black-and-white digital prints showcasing several different fish species.

Moray eel. Moray eels are legendary predators on coral reefs. Note the second set of jaws in the “throat”; these are the gill arches, which are present in all fish. Gill arches support the gills, the major respiratory organ of fish.

Lookdown. Because of its sloped head and the enlarged crest on its skull, the Lookdown appears to “look down” as it swims. These fish often swim in small schools.

Alligator Pipefish. Pipefish may be thought of as seahorses unfurled. The numerous bony body rings are used to differentiate one species of pipefish from another.

Ox-eyed Oreo. The name Oreosoma (“mountain body”) refers to the cone-shaped bony structures on the underside of this larval specimen. Adults are more elongate, less oval, and covered with scales.

Dhiho’s Seahorse. Just over one inch long, this elegant fish is readily identified as a seahorse by its characteristic head. The body ends in a tail that can curl around and hold on to algae or coral. This species is found only in the waters around Japan.

The “X-ray Vision: Fish Inside Out” exhibit is inspired by the book Icthyo: The Architecture of Fish: X-Rays from the Smithsonian Institution (Chronicle Books, 2008) by Daniel Pauly, Lynne Parenti and Jean-Michel Cousteau.

Exhibit Tour Itinerary:

All images by Sandra J. Raredon, Division of Fishes, National Museum of Natural History.

To see other X-ray photos visit the Smithsonian National Museum of Natural History’s flickr page.