To properly stock a 29 gal
tank you should limit yourself to no more than 4 small fish (2"-3" or less in finial size). Stocking capacity is much lower in SW
than in FW
due to a few reasons. 1) saltwater has less disolved oxygen so fish sufficate faster if they are in a heavily stocked tank and water flow is lost. 2) in the wild there is more room for fish to live and thus most SW
fish are fairly agressive in their nature.
Ideally for flitration you would go with a decent skimmer like an Aqua C Remora, 40-50lbs of live rock, 3-4" sand bed. Additional water movement should be provided by a few powerheads or you could use a sump and the return pump woudl provide the water current. A good starting point for water current should be 10 X the water capacity of the tank. So for a 29 gal
tank a minimum 300gph should be moving in the tank. The ocean currents are very strong so SW
fish are used to such movement and some require it for their well being.
If your serously looking into SW
a small investment to make now would be in a good book like The New Marine Aquarium by Michael S. Paletta
or The Conscientious Marine Aquarist by Robert M. Fenner
these books will be of great value when your in the intial stages of planning your tank or even figuring out if you are ready to take the dive.
Things you will need will include: