That does look like a tiny fry. It moves so strange, lol. But I'm only use to goldfish and gt fry.
What are all the possible options on what it could be? This will be very fun to follow as it grows.
I am not sure what a "gt" fry is. New to the nomenclature here. However, I think I mentioned in my post, but if not, I'll repeat, that in most all tanks in the fish room, I had just been on vacation and so males were in one tank and females in another. However, there was only one tank that had both males and females together and that was Myleus Schomburgkii also known as "wide bar silver dollars" or "blue hooks". So that is the only possibility in my opinion, but in another month we'll know. If it was like from a Rosy barb or something else that the filter might have been exposed to, the question then arises as to how long can an egg stay dormant before hatching late? Just for the record, I know about killifish, but besides the Schomburgkii I only have barbs: Filament, Tiger, Rosy, Snakeskin, Checkered, Odessa, etc. I have yet to read about someone successful with breeding Schomburgkii. I will post a new picture of the fry in question soon.