Agree with reefman13, D200 will give you much much better experience than D80.
( I own D200 and having a couple weeks experience with D80)
D40x is more like an entry level for new dslr user, capables of taking stunning pictures...a very good choice for someone who is a little bit short of budget.
Skip the kit lenses if you really expect the best out of your camera.
AF-S DX 17-55 f/2.8G IF-ED for mid range lens. Exceptional lens ! (rumor says that a new version is coming out with VR tech. equipped, you might want to wait and see)
AF-S VR 70-200 f/2.8G IF-ED for long range lens, equipped with VR which helps a lot when taking fast moving objects (like your fishes). I personally call it a "legendary lens".
AF-S MICRO VR 105 f/2.8G IF-ED for macro lens, it wouldn't be too much to call this lens "Nikon best macro lens, ever!" (I own 105 f2.8 and 60 f/2.8 and and this 105 vr f/2.8)
18-200 vr don't really give you "the best" image quality, but you will love the versatility of it.
(I love it, I do own one)
I don't want to go too far but the first 3 lenses can normally be found in any professional photographers already. I'll leave the rest for other members.