Midnight Aqua Canvas is a nice collection that includes 20 high quality icons based on three photos that have been taken at an Aquarium.
Every volume (disk), application, file, and folder on your Mac is represented by an icon. Volume icons tend to look like the item that they represent, for example, your hard disk looks like a hard drive, CDs and DVDs look like discs, and removable drives look like removable drives.
Midnight Aqua Canvas icon set allows you to give an original touch to your desktop no matter the file types or applications you choose to associate.
To learn mode about changing your default Mac OS X icons you can access the Apple Support page HERE.
NOTE: Midnight Aqua Canvas icon set is for personal, non commercial use only.