Most people agree that rosey red minnows are a good feeder fish, though I have given my turtles common feeder fish as I have not seen these minnows in stock. Goldfish are fatty so stay away from them, however.
Yes, they usually have a special tank at the end of the wall labeled rosey red minnows, if not, it's the tank with hundreds of small fish swimming in it, usually pink or silver in color.