What lens for Reef Aquarium close up and Macro?

[Steve Ruddy]

I'm going to purchase the Rebel XSi when it comes out and my first lense I will be using for shooting corals in highly illuminated reef aquariums. The corals will be anywhere from 2'' - 20" from the front glass. I would like a lense that will be able to fill the frame with about .25" or less section of coral from most anywhere in the tank. I also would like to take further out shots as well. Is this a one or multiple lens application? My G2 with a 250D close up lense did fair but didn't get that close.

[phirefly]

For macro shots of my corals, I love the 100mm macro lens

[Steve Ruddy]

For macro shots of my corals, I love the 100mm macro lens

I was thinking that lens maybe apropriate. Do yo ever use extention tubes or teleconverters to get an eeven larger image when needed? Have any shots you would like to share?

Thanks,

Steve