could anyone tell me what age does a great dane puppy stop growing as i have been told 12 months out of a book and someone has told me 18 months then they start to fill out. my puppy is 29 inch to the top of his shoulders and he is only 10 months old.

They tend to grow really tall really fast :) I don't think he will reach full maturity until at least ten. Willis was a long tall sally until he got to 18 months and now, at 2, he's really filled out. Remember he doesn't need to carry a lot of weight yet as it will put more strain on his joints :)