Walmart sells them online. They're called Hawkeye 5 Gallon Hex. No, I use a gravel that's made for plants. It's called Active Flora. I found it at a local fish place. Eco complete is another wonderful plant gravel.
I started out different on my big 16 gallon. Gravel, silk plants, but I changed it all over to live plants and plant gravel. You can honestly change anything you want. :)
Where ever did you get those amazing 5 gal. hexes? :D They're gorgeous and stout and perfect for betta! And you planted them so beautifully!
Are you using the walstad method? Because I'm just starting my tanks!
I wish I'd planned them better!