It looks good. Most people would be very happy to have a layout like this in their home.
The main critique I have is that the layout doesn’t really have one compelling focal point. It has two areas with very heavy visual weights and a central area negative space. All these areas are competing for our attention and though it’s fine to have multiple focal points, one of them should be dominant.
Here‘s a well executed aquascape with a similar concept. I think would be a good reference for your layout.
This layout does a lot of things right, but what I’d take away from it is how everything is working together to draw your eye towards the end point, the negative space at the top of the aquarium.
This is how I think everything should flow to create the composition. Personally, like above, I would make the negative space / end point the main focal point as it should enhance the sense of depth and flow of the layout.
Here are the adjustments I would make to this layout. Firstly I would shift the wood, circled on the right side, to the left just a little bit. This should close up the area of negative space and make the layout less symmetrical by adhering to the golden ratio. Hopefully this should also increase the dominance of the end point. In addition, I would try to emphasise the central pathway, by adding some rocks in the places I shaded blue narrowing the path as you go further back. This should frame the end point and simultaneously enhance the depth of the layout. I would also remove the rocks shaded in red that I think either detracted from the wood‘s impact or from the flow of the path.
Finally, I illustrated some of the planting I would suggest. The shape of the stem plants is supposed to frame the end point further, but will change if you shift the wood like I suggested, but the principle would be unchanged. There’s another circle on the left side and I’m not too sure about this area. If left as negative space it could add some interest particularly from other angles and also reduce the symmetry of the layout. Then again it might be distracting from the main focal point.
I hope this is helpful and post some pictures if you make any changes