I posted this in your other thread but I'm saying it again here incase you missed it:
Honestly fishboy, I think the best course of action would be to return the mollies and danios and turn this into a betta tank with a few small rasboras or tetras. The mollies are going to get too big and boisterous for that size tank and bug the heck out of the betta, danios prefer cooler temps whereas bettas like it really warm, danios like lots of current and room to swim, bettas don't like current, danios can nip, mollies and danios are fast feeders and the betta stands little chance of getting much, mollies like harder water and some even prefer brackish (slightly salty) conditions which doesnt suit danios or bettas... Do you see where I'm coming from with this? It's possible for you to have a good tank you enjoy, twenty gallons is a decent size to work with, but the fish you have right now just do not work together