there's definately a line between sw clubs and aquarium societies. it seems fw enthusiasts don't care about sw, and there's the sw enthusiasts that don't give a darn about freshwater.
I used to work in a LFS and some of the veteran sw guys have never had a fw setup, they don't even know how to set one up, nor do they care! then there's the odd few people that do both
that's the real fish enthusiast!