I suppose it’s time that I disclose a secret passion of mine, and one I’ve kept out of public view (well, mostly) for many years: yes, I’ve maintained a fascination with eels for many years now.

Some might consider this a strange hobby, but the reason behind the interest is simple: years ago, I had run across an item of interest from the annals of ichthyology, in which the story of a very large eel larvae (otherwise called leptocephalus) had been found among the fish in nets brought aboard the research vessel Dana near the Cape of Good Hope by researcher Anton Brunn in January, 1930.

The specimen in question was a little more than six feet long, which at the time seemed impossibly long for any known variety of eel larvae; they are normally about 1/32 the length of the adult variety, the longest of which seldom exceeds just a few feet. Hence, Brunn reasoned that for the larvae to be so large, the full grown animal may be truly gigantic in proportion. For years afterward, many considered whether giant leptocephalus were indeed the juveniles of a mysterious — and massive — undiscovered species of eel that might account for some sea serpent reports.

This was not the case, however. Today, it is suspected that these large leptocephalus belong to a species in the genus Notacanthidae, the variety in question more commonly known as spiny eels. The existence of the fish-like spiny snub-nosed eel was unknown at the time of Brunn’s original discovery, and much like the tadpole that loses its tail with its metamorphoses into a frog with kicking legs, these particular eels can actually be longer in length while still in their larval stage, and hence the confusion about the “giant” leptocephalus.

I’ve maintained an interest in various eel species despite the case of mistaken identity described above, and in truth, there are still some instances where large leptocephalus have been discovered that still inspire debate over whether a larger, unknown species of eel might still exist (maybe not large enough to account for purported sea serpent sightings, I might add, but large nonetheless). Such ideas are entirely speculative though, and part of the problem lies in how difficult it is to chart and study eel behavior, particularly in our oceans, even despite the amount of data we have catalogued about various eel species, their life cycles, breeding habits, and changes that occur during growth stages leading to maturation.

More recently, I noticed that our leptocephalus friends had befallen yet another strange case of misidentification. The one I’m referring to has been making the rounds lately on social media, warning about a nearly invisible, worm-like parasitic creature, which might be found in your drinking water!

Ah, doom porn at its finest. Well, if it were true, that would be one thing, I suppose. Have a look for yourself and see if this “creature” looks like a parasite to you:


Most can tell from the fish-like eye that this isn’t some strange parasite; indeed, you’re looking at images of eel larvae here. As one can probably guess, these little guys have the benefit of being nearly transparent at this stage in their lives, which of course helps them prevent detection by would be predators, to some degree.

What’s even more amusing is that by Googling “leptocephalus,” one of the very first images that appears in search results is the panel in the lower left corner of the bogus graphic below, which depicts an image from the archives of the Mie Prefecture Fisheries Institute near Shima City, Japan. The same image was used in a SciTech Daily article in 2013, which can be seen here.

So no worries… while there may be other things (more likely of the microscopic variety) that may end up in drinking water from time to time, we can rest a bit easier knowing there is no threat of misidentified “parasitic” transparent baby eels slithering down your gullet any time soon.

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