Sooooo I have an odd question…
What kind of snails are these and how the heck did they get here. I have not added/replaced anything since the beginning of December 2020. Never had snails and have never seen them in my tank. Today I see 3 of them. One crawling and then these two down in the rocks.
LOL, jake. Those are MTS, Malaysian trumpet snails, & as jake alluded to, mostly nocturnal. They are livebearers & don't really bother anything unless you over feed. If you don't like them you can pick them out & throw them in the trash or even your yard. You could have had tiny little 1s for quite some time but they sure show up well in you black substrate .
I kind of like a few down in the sand/gravel to eat any leftover food & aerate substrate. I have pretty soft water & most don't usually get full sized for several years (~1/2 inch or so). I just noticed a biggish 1 in a tank that's been set up for 9 years. In harder water with more food they will grow & reproduce faster.