Nex-3 macro lens help

[Magical Reef]

I have a Nex-3 and I want to start taking some macro shots. I know nothing about it other than that I need a macro lens. I posted a couple of times in photography forums but they don't understand the lighting intensity or the terms I use when talking about reef tanks. Is the Sony 30mm f/3.5 Macro Lens good enough? I read that you have to get the extremely close to the object with this lens. Is this true? I'd like to shoot within a foot or so of the object and have the ability to zoom in and catch a macro shot. Since I'm brand new at this I'd much rather keep my costs down in case I dont care for it. If there are other brands that you suggest please let me know. If there are any attachments that I need please let me know as well. I just want to make sure that I buy exactly what I need the first time. I really appreciate your help!!

 

[Misled]

Around 100mm tends to be best for shooting tanks. I don't know what Sony carries, but I believe the Tamron 90mm and Sigma 105mm are made with Sony mounts. Both are very nice lenses. A tripod is also a must. Flashes can be fun, but you can get away without them. A true macro doesn't come in zoom models. A true macro will have 1:1 magnification.