My pleco is fine. Doesn't suck on the other fish or anything, and I give them plenty of food.
I agree with you on the grocery shrimp, and I want to get him off it ASAP now. I read the back of the bag, and one of the ingredients was sodium tripolyphosphate... which is a very bad thing (for fish AND us).
Need to find a place that sells fresh and/or organic shrimp. Not sure where I could get some live blackworms locally, but I know a place I could get them online. He wont touch nightcrawlers or red worms though, even if they're cut up.