Yes, a fish tank is less complex... that means it has LESS potential configurations and possibilities.
Despite what you think, the presence of 'cosmological and biological factories' does mean that there are far greater possibilities that can emerge as a result of the interaction of matter and energy within the system.

Have you ever heard of the game of life? Here it is:


This very simple system is capable of spontaneously forming complex structures, capable of movement, and self replication. If such a basic system can produce these things, imagine what the universe can produce given billions of years.

"Again, so god created the universe and thats it, or also started the process of evolution, a bit like the opening scene of Prometheus?"

You're still not getting it. I'm not talking about aliens coming to Earth and seeding life, I'm talking about a God that created the universe itself. If God is all knowing, and created the laws of nature/physics, then it logically follows that he predetermined everything that would occur. Get it?