Originally Posted by opacwhite
just saw this and i know its old no idea if you made your thing or not but i had the same idea a few months ago and made my corner tank into just what your thinking of i think here is a pic of it i like the way it turned out and am thinking of putting some type of small fish maybe a betta in it
That looks really good!
I can't tell from the picture how much water volume you have though. Looks like it might be pretty small even for a betta. If it's a few gallons of water it would be ok though.
Of course you appear to have a water fall, so you now have natural biological filtration by the water running over the rocks. But you will still have to keep in mind it will take about a month to fully cycle after fish are added (or better yet do a fishless cycle) so you'd have to watch your water perimeters and do water changes until it cycles fully.
The plant growing in your rocks (I'm assuming it's also real) would also help filter any nitrates out of your water. Any plant whose roots have contact with the water in fact will gain nutrients from the water.
Do be careful, of course, about the mulch or any fertilizers you use getting chemicals into the water though.