The famous nocturnal Hex hatch of the Midwest (and a few other lucky locations) stirs to the surface mythically large brown trout that only touch streamers for the rest of the year.
PaulRoberts on Jul 16, 2016July 16th, 2016, 4:15 pm EDT
Filmed in a freshwater pond in Colorado. It is likely a larval...something...and appears to be around a bit under an inch (20mm) in length. It appears to be nearly transparent, long thread-like tails, and a smooth gliding swimming behavior. I took a wild stab at a Gastrotrich, but an expert in Italy, Antonoio Todara, didn't think so. "Too big", he thought.
PaulRoberts on Jul 25, 2016July 25th, 2016, 3:13 pm EDT
Hi Luke! That's the best guess so far. Long, lean, gliding, and transparent would describe both critters.
The cons are: Supposedly they don't do well with fish predators around and there are plenty of bluegills and bass in this pond. And, fairy shrimp are pretty fast swimmers, I think. The guy I recorded was cruising pretty slow.
Jmd123 on Jul 26, 2016July 26th, 2016, 8:13 pm EDT
A transparent larval fish of some sort, perhaps a baby lamprey, or other eel-like species? Or a baby bowfin?? I mean we're talking just out of the egg here if that's what it is...??? I see a very slight degree of undulation, but not much, like the swimming leeches I saw today. I go for larval fish of some sort.
Jonathon
No matter how big the one you just caught is, there's always a bigger one out there somewhere...
PaulRoberts on Jul 27, 2016July 27th, 2016, 5:47 pm EDT
I'd considered that Jonathon. I looked at larval gizzard shad and carp (this is a warmwater pond), but I didn't see a fit. Some saltwater fish have leptocephalus larvae that free drift before undergoing metamorphosis. Shad have fairly "underdeveloped" larvae, but they didn't fit.
Martinlf on Jul 29, 2016July 29th, 2016, 3:46 am EDT
Another mystery. It amazes me that for all we humans know, we still run into things that we can't explain. Oh, I assume somebody would know what this creature is, but it doesn't seem to be very easy to identify for some pretty knowledgeable folks. Love it. Thanks, Paul.
"He spread them a yard and a half. 'And every one that got away is this big.'"
PaulRoberts on Jul 29, 2016July 29th, 2016, 6:14 am EDT
Thanks, Louis. A bit off-topic for a trout focused site, but I was stumped. My best stab was a Gastrotrich, so I contacted a world authority. He didn't know what it was, only to say it wasn't a Gastrotrich. I have no more guesses so I thought I'd shoot it out here where reside people who are interested and willing to delve into cool things, even those tiny and complex. Thanks for trying all. It will remain labelled "strange critter".
Entoman on Jul 29, 2016July 29th, 2016, 9:08 am EDT
Hi Paul,
Were there a a lot of tails or just a few? Were mandibles noticeable or not? Were there any noticeable legs or other appendages? If it weren't for the size I would have thought phantom midge larvae, but it still may be dipteran of some kind...
"It's not that I find fishing so important, it's just that I find all other endeavors of Man equally unimportant... And not nearly as much fun!" Robert Traver, Anatomy of a Fisherman
PaulRoberts on Jul 30, 2016July 30th, 2016, 3:18 pm EDT
Hi Kurt,
I have no anatomical details to offer, only the video posted. I know it's not much to go on.
Phantom midge is a good guess: transparent, elongate, open water. But the vids I watched of them show them with a twisting swimming motion, like mosquito larvae.