I have 6 botia sidthimunki at the moment and they are a lot bigger than 2".
They cost me £10 each
Lovely fish. Like to be kept in a shoal though.
I don't think you will get a loach as small as Corydoras pygmeaus. If there is I certainly haven't seen one in all my 30+ yrs in this hobby.
Yeah according to Loaches.com Sidthemunki are on the IUCN red list.