Hello everyone, I have wanted to get into the hobby for years and am finally diving in. I have a few questions: 1. I have an old 20 gallon long, 18 gallon, and 46 gallon tank, which one would be better for me to start off with? 2. would it be better for me to use sand or gravel for it? 3. what would be some good stocking for the tank? I am willing to have fewer fish for bigger fish but want at least 5. Thank you in advance.