Welcome to the Inside: SereneScreen forums!!
Marine Aquarium 2.5 is a bundle of Marine Aquarium 2.0 and Marine Aquarium Time/Crystal/Clock 2.0. I am not sure why they called it 2.5. In the coming weeks, Marine Aquarium 2.6 will be made available on the website which includes everything you have now plus 2 more fish.
Glad to hear that you like the product. We're pretty fond of it too.
The coral/plants don't move right now. Maybe in a future version.
Welcome to our community and we hope you'll stick around. We talk about other things too.