Filefish are so named because they have skin a bit like sandpaper or a nail file.
From the bbc.co.uk
The threadsail filefish is an omnivore, and can feed on plant or animal matter.
From the en.wikipedia.org
In the Canary Islands the growth and ageing of the planehead filefish have been studied.
From the en.wikipedia.org
Parrotfish, filefish and sergeant major fish prowled through the water as starfish lurked on the bottom.
From the post-gazette.com
The planehead filefish can be used for human consumption.
From the en.wikipedia.org
This is an orange spotted filefish.
From the bbc.co.uk
Stephanolepis cirrhifer, commonly known as the threadsail filefish, is a species of marine fish in the family Monacanthidae.
From the en.wikipedia.org
For sashimi, we received a generous selection of sliced filefish with steamed monkfish liver, fatty tuna and sea bream over a bed of lime.
From the bloomberg.com
More examples
Narrow flattened warm-water fishes with leathery skin and a long file-like dorsal spine
Filefish (also known as foolfish, leatherjackets or shingles) are tropical to subtropical tetraodontiform marine fish of the diverse family Monacanthidae. Found in the Atlantic, Pacific and Indian Oceans, the filefish family contains approximately 107 species in 26 genera. ...