Congrats on the CPO!
If I'm not mistaken, they should breed easily. Just gotta figure out what's going wrong.
I have a hillstream tank, wasn't trying to breed the hillstream loaches, but saw a bunch of fry in the tank. Was happy to see all the little guys swimming around. Did a water change and filter maintenance later on and upon removing the biomedia and pads out of a HOB, I saw a few baby hillstream loach fry swimming in the settled mulm inside the HOB. Then I put them back in the tank.
I am surprised they survived being sucked up by the filter intake and not getting shredded by the impeller (this filter design seems all the water flows through the impeller, not just the impeller drawing water into the filter). Wasn't planning on them breeding so I had no prefilter on. Hillstream loaches are my favorite fish too so it was exciting to see the little rascals are all happy and creating little ones of their own.