I do use the macro setting, and as for lighting. Sometimes I use flash, and sometimes not. If you don't use flash, it is hard to get a clear picture (especially if the fish is a fast one). I mostly use the flash and get up pretty close to the glass at an angle (always!) to make sure I don't get a reflection of my own flash or anything else - like my hand or something. I just make sure it focuses, and that I am aiming through the glass at an angle, and I take the shot. Although I must say ~ I have tried working with other cameras, and found the one that I use to be highly efficient with pictures in the aquarium - ohter cameras were kinda stubborn to me (either too bright, won't focus, etc.).
The fish with the toothy grin is an African Tiger Fish - def one of my favorites!
Thanks for all the compliments, and thanks for pointing out the properties trick!