i just don't know which ones ha. i have two tanks that i want to add a pleco or two to. one is a 300 gal. acrylic, so i don't want anything that would destroy it. it is scratched a little as is, so i'm not too worried i just don't want to come home to a tank that looks like it had a grinder run on the inside of it. that tank is a comm. tank no real aggression. the other tank is a 120 gal. glass tank with one fish, a red tiger mota, he's not real friendly. i don't know if he would bother a bottom dweller or not, i do know he won't tolerate other cichlids or arrowana. let me have some ideas. btw if the mota did get rough the pleco would be moved to a 125 gal. so no worries there.