@ Don :
not to bad at all. I really like the blue-effect of the background, is that a reflection ?
And you picked 3 real waterplants, could have been worse.
Just 2 remarks.
1) If you choose smaller rocks, the tank will look bigger. The large rocks make the tank look smaller than it already is.
2) I could be wrong, but from the picture, I think the gravel you used is a little coarse.
English isn't my native language, but I guess you already noticed that :-)