Just in case anyone is curious, my CBS love blackworms. I don't know about BPS or RCS yet, but I saw the CBS wrestle around with one and carry it off and it looked like it was eating it. The worm escaped at one point, the CBS was eating something (probably a segment or two), and then went after the worm again. I stopped watching and at the end of the night, the worms were gone (I put about 6-10 worms of various sizes into a tank of about 50 shrimp). I had BPS in there, but didn't see them eat any.
I did not see if my BNP eat any. I just sold my L129s, I'm sure they would have eaten them, but my BNPs had no interest at least while I was watching