If you are seeing 2fps, then the Aquarium is switching into emulation mode and not using the 3D capabilities of your 3D card at all. Try installing the Aquarium as a screen saver (copying it to \Windows\System32\) and executing it from there. (Or, if you have it installed this way right now, try moving it OUT from that directory).
I don't understand what you mean about .99H. Can you explain in more detail the problem you are having?
The next version of the Aquarium (available this week) will probably solve your problems. If you have not already done so, you will want to upgrade to DirectX 8.0a and recent drivers for your GeForce DDR so you can use this version.
And I highly recommend upgrading to the 6.47 or 6.54 nVidia drivers from
www.reactorcritical.com/
The 6.50 drivers at
www.nVidia.com are terrible.