Hello, I have a 20 Gallon tall aquarium. Right now I have nothing in it. I’m going to put a Giant Betta in it, but I was wondering if I could do neon tetras with it, if so. How many can I do? And can I put corys with it as well? I like the way neon tetras look but but I also like the Corys at the bottom. I really like the Julii Cory and Panda Cory.