Using Sony DSC-W120 - Was: Any thoughts?

[vic622]

Yesterday, I took some shots of a new addition to my tank and this is the best image I was able to come up with.

One thing I couldn't capture, is the little tufts on the first 6-8 dorsal spines. He also has a pair of these tufts on his snout, just below his eyes.

I'm using a Sony Cybershot DSC-W120 7.2 megapixels & I'm still experimenting on the best combination of settings. This photo was taken on program with ASA 100, macro, spot metering, low flash level, spot auto-focus, +0.3EV (underexposure), outdoor white balance, vivid color mode.

Still, I needed to crop, push the color saturation & temperature to get the shot I've posted - the only one that came close to working out of 12 or so I took.

Should I try using the tripod & the 0.5m (1.7ft) preset focal length & a tape measure (or a string) to get the right distance?
This image was the sharpest of the batch, but it still seems to not be crisp. Does it look like its outside the depth of field, or is it camera shake?
Without knowing the f-stop, can I figure out the depth of field?

Any suggestions?