Someone has asked me about setting up a 10g fresh water aggressive tank, and I know nothing about it. My first question is what is an aggressive tank? It has to be more than a tank with fish that fight each other. Is a 10g too small for such a tank? I'm waiting for him to bring me a water sample before asking stocking questions, but it's well water and I'm pretty sure it's soft. I'm also pretty sure he wants it because an aggressive tank sounds cool to him, with him knowing as much about it as I. Maybe it's not an advisable project for him or maybe it is, I don't know what to tell him. If someone could fill me in, I could keep him on the right track. Thank you.