Nice job. It looks realistic.
If you don't mind a suggestion, and could stand to not have an oil slick on the water, get a small jar of Mod Podge craft acrylic from Wally's crafts section and stipple some of it on the top of your glassy water. When it dries, it will dry clear and it will look like naturally rippled water surfaces.
If you'd like to do this, you'll need the 'gloss' Mod Podge, and a disposable foam brush about an inch across. You pour on a thin layer, spread it around well, turn the applicator onto its flat side, and tap it along the spread layer. It will look rippled when it dries.