I've done several 1/2 gallon and less tanks/bowls. My advice is to over plant and go slowly, a cycle will take MUCH longer in a smaller volume of water. (that being said, I've successfully introduced cherry shirmp into a 1/4 gallon no-cap dirt cube that was only days old, go figure) It's hard to scape in such a small space, but it's a very fun challenge. And if you don't like it, redo it! It's easy with small things.