Originally Posted by fort384
Yes, tripod and remote shutter.
What iso setting would you recommend?
You're definitely on the right track with the tripod, shutter release, and shooting in RAW. Don't forget that in RAW, in addition to exposure, you can also adjust your white-balance, since dSLR's dont have presets that match most of the lights we use. You can really bring out some truer colors with WB adjustment in post-processing. What program are you using for processing?
As far as the ISO, the lower the better. The trade-off being longer shutter speeds at a given f/stop, but the image quality is better (less grain). If you're not doing so, shut off all your tank pumps while shooting.... this allows the corals to sit still to prevent motion blur with the slower shutter speeds.