On the outside, the pinecone fish has a pale yellow to whitish color with black outlines on its scales forming a network of patterns with spike running down its sides.
But a new scan reveals that these spikes aren’t just on the outside – most of their skeleton is armor as well.
The armor of the deep-sea, nocturnal fish is built from smaller bony subsections called scutes that form a series of backward pointing sharp scales on its body.
The researchers used computed tomography (CT) scanning, a method that creates cross-sectional images of specific areas of a scanned object without requiring the user to cut the object. It revealed that the fish’s skeleton has a layer of spiny armor built from smaller sections
The scan of the fish, also known as the pineapplefish (Cleidopus gloriamari) in reference to its markings, was posted on Twitter by Matt Kolmann, a University of Washington Friday Harbor Laboratories researcher.
The subtropical fish is often observed in shallow coastal reefs and also in deeper offshore waters.
It’s distributed in the Eastern Indian Ocean to the Western Pacific near Australia and can grow to about 22 centimeters (8.7 inches) long.
Aside from its striking rows of spines, the species has pale, luminescent organs on either side of it lower jaw, which produce produce a bioluminescent greenish glow that reportedly change to red as the fish ages.
The researchers used computed tomography (CT) scanning, a method that creates cross-sectional images of specific areas of a scanned object without requiring the user to cut the object, to scan the fish.
![Aside from its striking rows of spines, the species has pale, luminescent organs on either side of it lower jaw which contain symbiotic bacteria that produce a bioluminescent greenish glow that reportedly change to red as the fish ages. Pictured is a pineapplefish at Monaco Aquarium](https://i.dailymail.co.uk/i/pix/2017/12/01/19/46E2D71700000578-5137371-image-a-26_1512155485836.jpg)
Aside from its striking rows of spines, the species has pale, luminescent organs on either side of it lower jaw which contain symbiotic bacteria that produce a bioluminescent greenish glow that reportedly change to red as the fish ages. Pictured is a pineapplefish at Monaco Aquarium
It revealed that the fish’s skeleton has a layer of spiny armor built from smaller sections.
Kolmann told the DailyMail.com that him and his team have ‘no idea why these fishes have such extensive armor,’ but that it it might help defend the fish.
‘We know very little about so-called “twilight zone” reefs, where these fishes live… generally deeper than 150 feet.’
‘We think the armor must serve some defensive function, but defense from what is an interesting question.
‘Most of the research on armored fishes states defense from predators as being a reason for armor, but myself and collaborators are exploring whether armor might serve other functions, perhaps as defense against competitors within the same species.’
![The pinecone fish specimen was a loan from the the California Academy of Sciences, as part of an initiative called #scanallfishes started by the University of Washington's Friday Harbor Labs' researcher Adam Summers](https://i.dailymail.co.uk/i/pix/2017/12/01/19/46E2D70200000578-5137371-image-a-25_1512155481134.jpg)
The pinecone fish specimen was a loan from the the California Academy of Sciences, as part of an initiative called #scanallfishes started by the University of Washington’s Friday Harbor Labs’ researcher Adam Summers
Kolmann told Live Science that while the fish is ‘really weird’ for many reasons, his research team focused on the skeleton because they’re interested in the way that bony armor evolved in fish.
‘It’s incredibly intricate, seemingly ornate, thick, overlapping plates,’ Kolmann told Live Science.
‘We knew from seeing them in collections and in aquariums that they had armor plating, but there’s something about seeing the skeleton by itself where we realized, “Oh, man, it seems like the majority of their skeleton is armor.”‘
The pinecone fish specimen was a loan from the the California Academy of Sciences, as part of an initiative called #scanallfishes started by the University of Washington’s Friday Harbor Labs’ researcher Adam Summers.
Kolmann has been using CT scanning to analyze fish anatomy for many years, and he says his lab has scanned 2,500 species so far.
Now, the #scanallfishes is being used by other researchers to post CT scans of fish.