Isn't Aquarium just one of the frontends for Rybka. It is my understanding that Chessbase does, or will, offer a Fritz-like frontend specifically for Rybka, and that that Russian company that makes Chess Assistant will offer it (it being Rybka 3) with Aquarium as its frontend.
In either event, good luck finding an intstruction manual printed in English.
In the interest of full disclosure, I haven't used Aquarium. I've only read about it thus far. I am using Rybka 3 as the main engine in my regular Fritz 11 game.

Anybody out there using Aquarium (i.e. the UI designed for sale with Rybka)? I'm curious to hear what people think of the interface itself, especially in terms of how it would compare to Fritz, etc.
I've read some of the articles on ChessCafe, and it seems like there has been some genuine innovation here. (?) Thanks.