I have 6 neon fish. An albino scavenger and a leopard looking scavenger (sorry I don't know the technical names). I don't know what I want in my larger tank yet I would like to add some plant life and make it colorful. My larger scavenger had an internal parasite so I researched and treated the tank by soaking their food in garlic water. I was surprised that it really worked. Fish are doing much better now.Hi and welcome to the forum
What fish do you have in the 5 gallon tank?
What fish do you want for the bigger tank?