My point and shoot isn't cutting it. I'm glad you posted. I'm looking at SLR's. Used to do alot of SLR stuff with regular film in high school.
You have a black frame around them, did you photoshop them? How much tweeking was necessary in photoshop if you did?
The first pictures seemed to have some depth of field problems. Might play with your f-stops. If your taking pictures of a single polyp then blurring the background is okay, maybe even desirable, but when the picture looks like your trying to show the whole colony, having the foreground in focus and the background polyps a little blurry looks like you messed up. Just my opinion.
Mike