Kaiden's Cardinal Fish
I have 2 spotted/PJ cardinalfish out of 9 total in my 75. Yep, they don't "do" much but hang out, but fill in some areas, so I'm glad I've got them. They are not aggressive at ALL! My Kole chases the Foxface around, my Maroon Clown keeps her territory clear, the blue-green chromis and bartlett's seem to hang out together and my fairy wrasse goes solo. In general, they are carnivores that fill a niche in the tank.
Now that I checked the name, yes, I plan to get a single Kaudren for my 25...