I'm assuming he's a normal grey cockatiel then? Petco usually has the birds' hatch dates written on their *cages*. At least the Petco I go to does. It would be nice to know how old he is, but in general, from what I've seen, Petco's tiels are normally 3-6 months old.

Be sure to start feeding him veggies (broccoli, carrots, peas, corn, etc.) and pellets at an early age. They get stubborn if you start late, and they need those foods in their diet. I'm sure he already eats seeds as well. Is he already tame? Good luck, and if you have any tiel questions, feel free to ask! I'm going to bug you until you post pics! Can't wait to see Charlie, the new PT feathered baby!