I got this from another forum but thought I'd share this. Anyone notice their plecos mainly fancy ones panting or breathing hard. My large 10 inch l-114 was doing this. It was in an 80 with 2 other L-114's an L-14 a bristlenose and 8 adult mascara barbs. I read that plecos need large amounts of O2. Also a large bioload will cause nitrate buildup hence clogging the hemoglobin from transporting oxygen through the plecs bloodstream. I sold off 5 of the barbs and kept a trio of largest 2 males and 1 female. Also gave my neice 2 of the small L-114's. So my L-114 is in with a 5 inch L-14 and a 3 inch bristlenose and the 3 mascara barbs. Result is he is on the move more and barely see him breathe except when eating. He is the main fish in the tank anyway so I will definately keep this tank stocked lightly. Sorry for the long post.