Let me start off by saying I'm running a 10gal as my first tank. A few quick tips I could give you is Cycling your tank. Look up the nitrogen cycle on google and you will learn. During this cycle you SHOULDN'T put fish in. Usually takes a month at the most. Also, if you have fish in already make sure you feed them a variety of foods. I feed my betta worms, shrimp, and flakes/pellets. He lives happily with 4 frogs and 2 cory cats. Another tip is DONT listen to pet store employees. Whatever they tell is usually just to make a quick buck off of you.
I love my Frog! His name is Barfolemule. He's kind of lazy, but so am I!