I love the ceriths and trochus. Definitely active members of the cuc although my ceriths seem to prefer the rock (or my urchins back)
I have two fighting conches in my 75 as well.
I have a few ceriths already, but they may have ended up as emerald/hermit crab food... seems they go for them first instead of the bigger nerites.
Staying on the rocks is something I am looking for. My nerites would rather stay on the glass.
I am concerned about the cowries being able to defend against a few facetious hermits and an abusive emerald. From the looks, they cant close up all the way and have their fleshy bits hanging out quite a way... @najer do you have any problem with this?