How often do you change the water? How do you clean the tank? (Bowl?

) If you don't mind my asking. :)
By pebbles, do you mean marbles?
I wouldn't move him to the 29g, atleast not yet. Bettas can't be kept with many other fish as they can be very territorial. I wouldn't keep him in a 1g either. I suggest a 5 to 10 gallon, with filter and heater. It depends on where you live -- you may not even need the heater.