Welcome I suggest not doing the glow tetras because they are nippy I've never done snails but I have heard they are good bottom feeders I have a happy healthy 10 gal with 3 mollies and 1 african dwarf frog please don't blame me for the one we will be getting more beautiful boys are you trying a sorority it was quite unclear what you meant by sister betta's but I recommend atleast 20 gal for a sorority