Georgia Aquarium Frogs, Critique Welcomed!

Ok I thought I did a pretty good damn job on these frogs picture. I didn't have high expectations on these but when I viewed these on the computer they well exceeded my expectation. These were taken with my 50D + 100mm macro (non-is) and no tripod. All lighting are ambient light and cell phone continuous flash was used for the 4th picture because lighting condition was very poor. Critiques are welcome please let me know if there are rooms for improvement. Most of the pictures are only slightly cropped.