I have an ecopico that's about 5 gallons as well, and I wanted to know how the CPDs are handling it. Is 7 a good number for it? How are the nitrates? What/how are you feeding them? I read that these are finicky eaters. I ask all these because I saw that my LFS had these and I wanted to start introducing them to the tank. I've finished cycling and all I have right now is a Nerite snail.