Here’s my 20 long that I do nothing to at all. I just do weekly water changes and feed the inhabitants. The betta is Cassius and he can’t hold still to save his life. He lives with a bunch of wild Nerite snails, an Amano shrimp couple, and a few Least Killifish.
All the floating plants are Salvinia. I just threw out about 80% of what was in that tank. It kind of piles and scrunches up so you get at least 30-50% more than what you expect when it covers all of the surface. I’ll be giving it out by little deli condiment cups when the weather permits good shipping.