Every single fish I have ever bought at petco died.
Maybe it's the way you acclimated them. I barely buy fish from Petco, since their prices are a bit high. I normally get them from Petsmart.
I just happened to stop by a local Petco and they were out of the otos. I went over to another Petco and they had the same sale, so I assumed it was nationwide.
I'm sorry for posting if it's not.
125 gal (473 liter): Low Tech
(1.5wpg PC for 10 hours, no CO2/ferts, gravel substrate), Equipment
(72" Coralife PC, Eheim Pro II 2128 w/built in heater, FilStar XP3 w/Hydor ETH201 inline heater), Fish
(6*Discus, 2*Angel, 5*Clown loaches, 4*L-018 Gold Nugget pleco, 1*L-260 Queen Arabesque pleco, 7*Cories, Farlowella cat)