I never had cardinals before. Well....i had some when i was first getting into the hobby but they died. I really wanna get into so i want to know what fish could go with them, how to care for them, and the water parameters that they feel most comfortable in. i have 4 Zebra danios in my 10 gallon and im moving up to a 20 gallon high. My water parameter are Ph: 6.8, Ammonia:0.0 Nitrites:0.4, Nitrates:0.10.