The composition needs a little work I think. I may have even centered this little guy :) I like the green face sticking out of the muddy water. The blurry something on the bottom left is a bit distracting though.
Good color and detail. Don't know how you got him though, everytime I try to get some of these guys in the pond out back at work they jump away..guess you gotta be really sneaky.
I like the jewel-like tones in the frog. I wish there was a little more connectiveness between the high colors and the rest of the rusty tomes. He almost looks disembodied a bit, but a good idea.