If the store will let you, it might be a good idea to put a note card on the front of each species tanks, with the average adult size and weight of the animals, and the temps they are kept at to survive.
Maybe something that says "Hi, I'm a ____________. I can be quite a handful when I'm grown. I get to be _______ long and weigh as much as _____. I may not need the attention a puppy does, but I do need the care. I should have a cool area to rest in of ___ degrees, and a basking spot of ___ degrees. I eat ________ and like my water (still/moving/dripping). My favorite books on _______ care are __________ and ________. You can find them in the book section of the store."
Just a thought.