That shot was taken at f5.6 - try f8 or even f13 for more depth

You'll either have to slow the shutter - raise the ISO or boost the lighting. However much better on the lighting colour in this shot. Also unless he is being a very very still lizard I'd want to up your shutter speed a bit to minimise blur on his part (does his skin move as he breaths?)
Sadly this all points to needing more light on the subject - more flash
Thanks, lots of great advice (read your response in my other thread too, thanks!).
Here's where I've run into a few problems. I have the Canon XS, and on manual, it won't let me get that close, otherwise it can't focus. So for this shot, I put on it "Close-Up" mode, but that's all but using auto, as it locks in it's own settings, including the f/stop. I'll try manual again tomorrow, but the higher the f/stop, the less light in, and the higher I have to force my ISO (and then I get a noise problem).
Another problem is the focusing points. On manual, it only has one focus point, a square box, and it lets me focus mainly on the eye. But in the up-close mode (that's mostly auto), it switches to the 7-point focus system that has seven points on the screen and gets much more of the object/animal in focus. I've read and re-read that manual until my head hurt, and can't seem to find out if I can change a setting to achieve that 7-point focus system in manual mode (it'd solve a lot of problems for me photographic wise, if I could!).
My set-up is a 20 gallon aquarium on its side, with white or black poster board on the inside (depending which color I want to shoot with). I have two flourescent strip lights attached to the top, and a work lamp with a white light bulb (not the soft white that makes a yellow glow, but the more expensive ones that make a "cool white" glow). Here's a pic of the set-up (the photo makes it look way more yellow, it's actually not that yellow, it's bright white in person):
Any advice on how I can change, or better, the light box (without spending a fortune, unfortunately I'm a bit broke after the new camera purchase, lol). I was thinking two more strip lights, maybe one attached to each side? I'm saving up for an external flash, unfortunately I'm currently only stuck with the on-board flash, so bouncing any flash isn't an option.
BTW, the lizard stays very still during photo's. The two turtles, not so much.