Right now I have a pair of rams, an oto, and 7 cardinals in my setup. One huge thing to consider is the temperature rams require. I keep mine 83-84 degrees, PH 6.4, and have plants as well. Biggest lesson for me was plant choice. Make sure your plants are capable of handling the higher temperatures (rams may live at 80, but do better at slightly higher temps from everything I've heard/read). My first group of plants I chose melted, but now I have micro chain sword and a few others.