In my case it's been knocking not once, not twice, but thrice.
The first knock came shortly before the Black Friday sales: during my pre-sale local pet store scouting, in a tank of well-fed striped kuhlis that absolutely looked worth buying, were also a couple of neon kuhlis! The only other pet store I have ever seen carry them is not exactly convenient to go to, so getting these to increase variety was a must.
Plus they have a color very similar to dourada catfish/Brachyplatystoma rousseauxii, a fish I've always admired the color of yet don't even have available to me, nevermind the facilities to house. Some neon kuhlis ought to scratch that itch rather well.
The next knock came immediately afterwards, as I headed to the store to return a few kuhlis that failed to survive the 5 day warranty. I then happened to notice some surprisingly expensive weather loaches marketed as 24K weather loaches....and seeing them spurred off one hell of a chain reaction of thought!
1) The initial thought was that I adored their colors - they are more than nice-looking enough to justify their costs in my opinion.
I could not get a good picture of the fish at the store, so here is a link to a video (note that I do not use Facebook, I just found this) by Aqualogy LTD on November 3.
https://www.facebook.com/AqualogyLtd/
2) The next thought was that I had the door opened right back up to get some for my assorted-loach tank like I was planning 1-2 years ago. With temperatures in said tank ranging between 19-22C instead of more tropical temperatures, and the rest of the fish thriving in said cooler water, the temperature incompatibility issue goes straight out the window. And my additional concern about weather loaches being excessively prone to bacterial infections is likely alleviated too, because a discussion with the manager about said concern revealed that they are also concerned about it, specifically seeking fish in good health to order.
3) The thought after that was that I have never seen 24K weather loaches before. When I asked the manager about that, he said they were very rare, that he has never seen them before and cannot find anything about them outside his supplier.
I think this is about right. I found nothing about them either aside from Aqualogy (which may in fact be my pet store's supplier!)
4) The final thought was that they were at a larger than ideal purchase size, both in terms of time having the fish and fitting in a quarantine tank. What the manager told me is that he is specifically looking for some smaller ones (that will cost less as well), so it's a win all around.
I think a trio of these would be a good fit for the 473 liter given a dozen small/medium Botia and 40-60 kuhlis sharing the bottom, with them complimenting both the Botia and kuhlis nicely (and vice versa).
And for even better complimenting, having one of the three weather loaches as a 24K would literally perfectly complement the 2 other available color morphs of brown wild type and golden. It has brown spots like the wild type but also golden color like the golden variety - so I get essentially a crossbreed.
The final knock was the idea that this topic could be formatted Martin Thoene-style. As he's had multiple endeavors well-formatted in this way, and such a format has since become quintessential to Loaches Online, I aimed for it.
So I'm happy to say, when these opportunities knocked, I could open the door nice and wide.