I've had two BN Plecos in my 72 gal planted tank for almost a year. And with two swords and a load of other plants. Other than occasionally knocking a newly planted stem when they were rooting around like normal I've had no problems. It might be keeping them satiated. I do drop a few algae wafers or Hikari sinking tabs 1-2x a week and every 2 weeks or so cut a piece of english cucumber (this one does not cloud the water like zuch's or the regular "fat" cucumbers) and tie it to a small stone and sink it to the bottom. They find it in about 2 minutes. They LOVE it. It's almost gone in one day.