congrats on the pickup, not that you need reassurance but the d7000 is a replacement of the camera I love and have. It's an amazing camera, more than the average joe needs. now save some money for Prime lenses,

they'll cost as much, if not more than the body,
great pictures taken already. i don't do much of aquatics, but I do portraits. someone recommended a the 50mmf1.8, for the $$$, that's a great lens to start with. If you plan on doing more aquatic pcitures, the macro/micro lenses are the one's you'll need.