I have two clown fish, one firefish and a royal gramma in my 40 breeder currently. I want to add one more fish but I'm not sure what to add. I was thinking of adding a chromis but I read that they should be kept in pairs or groups and I don't know if I can add more than one. I am also considering a wrasse but websites suggest a 55 gallon tank for most of them. Will a 40 gallon be enough? I could always get a blenny but I kind of want a active fish that will swim around and I don't know how active blennies are. Any recommendations?