Anyway, Aquaman, I like it, I particularly like the bubble curtain at the back. If it were mine, I would add some more plants, the fighter will certainly appreciate it.
You don't have to fill it, both my tanks have open areas at the front, especially necessary if you have cories. Different plants, at different heights around the tank will still allow the fish to swim freely. The fighter especially will love worming his way through them, as well as having leaves to laze around on.
If you have a look in the voting for January's TOTM competition, you can see what I've done with my bigger tank. I have loads of vallis at the back left, 2 amazon swords at back right, and some smaller crypts and ludwigiaalong the back. Since that photo was taken, I've added another sword at the back right, and another alongside the filter intake.
Your cory are going to have a very difficult time of it on that gravel. They really prefer sand where they can just dive in. Plus, sand is a whole lot easier to keep clean.
Sand would look better! Also, make it so that the substrate is higher at the back of the tank, and lower at the front. This gives a nice depth to the tank.
I would add more plants too, and exchange to sand.
Yea my neons stay on the bottom huddled together I think they are. Scared of the fighter , he has killed a neon already... And how about the center peice a little cheesy I know but I like the ship.
Then either get rid of the neons, get rid of the betta, or put in so many plants they can't see each other. I'd be scared too if there was a murderer 12 inches away from me with nowhere to hide!