At the time I purchased them there was an abundance of alage in my tank. Although they have done a good job reducing it, there still is enough food for what I have, imo. I'm not sure how long BW had them. They were $1 each. Maybe they were just weak from nothing to eat at BW? The ones I could reach seemed to attach to rock just fine if I picked them up. The ones I couldn't reach have appeared to die .
I also bought a few of those large mexican turbos. WOW if it wasn't for their bulldozer additude, I think they'd be a big winner! They eat more then any snail I've ever had.