Not my cup of tea.
This isn't to be taken to heart, as this is just my opinion.
It is too bland for me, lacks color. To me, that aquarium looks like it belongs in a restaurant or something. I like eye popping stuff, stuff that makes you go 'wow, I want to do something like that'
The rock stacking is very nice, don't get me wrong, but the tank seems like it's focused on that.
This is a very good start though, throw a bit more in there, give the fish some stuff to swoop in and out of; oh and give it a background!