when i first got mine at an inch i kept them in a 29g but upgraded quickly to a 50g...they'll soon be going in a 100 as soon as my 300g and 500g come in...
you can keep any 1 to 3 inch P but will have to upgrade at 5 inches, and the more u keep the less time they have to be in your 29 gallon, try craigslist, they have good deals on 55 and 100 gallon tanks, good luck man