I have a blue crayfish, would like cichlids?

My crayfish is about 3.5" long, maybe 4. I would like electric blue cichlids. I know they are aggressive, but I don't know the extent. I'm not too worried about the cichlids, I have had tetras and mollies and guppies and platies with her, and as far as I know she never got them. Maybe one tetra. I'm more worried about the cichlids killing my cray. How big to electric blue cichlids get? If these won't work, is there a blue cichlid that isn't that aggressive and stays pretty small? (Pretty small being under 2".) I want cichlids because they have really nice colours. If you know of any other bright blue freshwater fish, let me in on that. Thanks!