Try not to be too defensive about my criticisms. I'm just trying to help. Take your time and follow along carefully as I'm going to start someplace unexpected.
Here's an example of a painting that has a single focal point that is very welcoming to the eye. There's no need to tell you what it is - your eye is immediately drawn to it. Then notice that your eye follows her suggestion to gaze down. You probably overshot the second overt subject but quickly corrected it. Why did you overshoot it? There's nothing there really, and yet there is. It's a subtle suggestion of the overall theme of this work which has a liberating undertone, especially considering the time and place it was created, 19th century France. But the second prominent subject, the dove, corrects your gaze so that you aren't caught looking at what you'd like to look at. This is masterful misdirection. But notice that your eye still returns to her unmet gaze.
This composition is a complex play of focal points. There are three of them and they form a triangle:
1. her face
2. the dove
3. her voluptuous, almost bare, breast
Notice that this triangle is very acute. It strongly points back to her face and your eye obeys. But, you feel compelled to follow her direction to look back down again. And yet, you are let down. Again. Your only consolation is the dove that is baring its breast, with wings spread open, embraced close to her chest. It's a very sexual work. You wish you were that bird.
But back to aquascaping...
What do good aquascapes have in common with classical paintings?
1. central focal point - her face
2. secondary focal point - the dove
3. supporting focal point(s) - her voluptuous, almost bare, breast
In this aquascape, there are:
1. central focal point - the left side trees
2. secondary focal point - the right side trees
3. supporting focal points - the path and the flying fish
Notice that the forest on the left of the bank is massive while on the right, it is slightly smaller so that it does not directly compete for attention. The path, while situated in the center, does not attract as much attention but is an important element that provides support for the two sides.
(That reflection of the tree on the water surface is obtrusive, don't you think?)
Here's another aquascape with similar elements. Is it as successful? Take your time to really look at it before reading on.
What makes this one less successful? It's the shape of the path, isn't it?
Why do you keep looking at the path? Because it's almost a straight line with a bulge that leads nowhere. The path is supposed to be a supporting element but due to its shape, it draws excessive attention to itself. Here's an example of what that path is doing:
When you see it, it's hard to look at anything else. He's clearly not the main subject and yet you can't help but not look at him no matter how much you want to. This is sort of what that path is doing, drawing unnecessary and distracting attention.
What are the focal points?
1. central (edit: I mean primary): the tip
of that rock, but not the rock itself
2. secondary: ???
3. supporting: ???
It's difficult to answer these questions. You can answer it using rationality, but that doesn't follow the eye. If you see what I mean, then what can you do to remedy these problems?