Michelle,
You could try Rick's in Frederick, Congressional Aquarium in Rockville, Tropical Lagoon in Silver Spring, or Aquatic Creations in Clarksburg/Hyattstown/nowhereville Rt. 355 between Germantown and Frederick.
There's also Go Fish in Rosedale, though I've never been there personally. Aside from that, there's Petco, PetSmart, and WalMart.
If you're willing to travel there's Centreville Aquarium and Vienna Aquarium in VA, and House of Tropicals in Glen Burnie.
If you're willing to mail-order them, WetSpot tropicals might have them, as might That Fish Place.
If anyone here knew where else you could find them, I'm sure they would've told you. This community is largely cichlid people. Most of us probably don't have loaches and some of us probably don't even notice them when we're out at fish stores.
Many of us are perfectly happy with the sponsors and have had very positive experiences with them so they are the first who come to mind. No one means any offense by it. By now, you must know that your harsh dismissal of anyone suggesting sponsors is offending to the members who make these suggestions with good intentions and to the sponsors, who do support the club.
Best of luck in your search for these fish.