Your Betta's are very smart fish and will love plants and decorations to explore. They can be hand fed too. There are videos on YouTube to train them to do other things too.
29g fresh with Betta, Kuhli's, Neons, Denison Barbs, ADF
, Mystery and Nerite Snails.
Some plants: Anubias, Java Fern, mosses and other misc.
8g Biorb with Betta and plants.
10g Mystery Snail Nursery
5g Plant grow tank with Pink Ramshorn Snails