Opah

I found this book entitled "The Riverside Natural History" that was published in the 1880s and filled with tons of really amazing images. While browsing through I stumbled on this interesting little guy:

That's right. He's the King of the Herrings.

So this of course intrigued me, and prompted me to look further in to this species. As it turns out, they don't seem to be related to herrings at all. Best I can tell, the closest taxonomic level they share is that of class, which encompasses every single ray-finned fish. Does the moniker mean that they lord over the herring with their vast size and appetite? Most likely not, as Opah eat mostly squid and krill, and the occasional small fish. Silly old book! Then again, they messed up the species name too, which they don't have much of an excuse for. Lampris guttatus  has been called as such since 1788.

(Image Source)

There are two species of Opah (also called Moonfish, Sunfish, and a handful of other names), both within the Lampris genus. They are also the only two living members of the family Lampridae. Opah are very large and very distinctly shaped, with their bodies actually being quite narrow width-wise. They are silver in color, with red fins. Opah can reach lengths of up to 6 feet from end to end.

Opah are found in tropical and temperate oceans worldwide, and live at depths of between 100 and 400m. Opah are believed to be solitary, and they are not fished for commercially. They are occasionally caught as a byproduct of tuna fishing, and most of the Opah meat sold in the United States is from Hawaii.

There really isn't all that much else known about Opah. There is no indication that their population is threatened or in a decline.