When is a garden too densely planted?

[dungeon]

Your setup is coming along nicely. Floating plants like frogbit would be a great addition for your betta, and they'll also help tone down the light on the Anubias.

[Lurcher]

I've always leaned towards using plastic or ceramic caves over real rocks in my tanks, mainly because I don't want to sacrifice valuable swimming space. To me, it seems like the 20-gallon tank could still fit a few more plants, but the 3-gallon betta tank looks pretty full, if you ask me.

[dungeon]

That Anubias is pretty large for the betta tank, consider moving it to the 20 gallon and then reposition the Java Fern behind the scuba helmet ornament - it'll fill out nicely over time.