Curiosity Killed the Catfish is up fairly often, about every 2-3 hours so if you're missing it at other times of the day it's just bad luck.

It's also not a problem even with a small group if people keep their heads. I've done it with a group of 5 on 2 different occasions. Pull the boss over to the wall instead of keeping it in the middle so there's less to aggro. Have everyone stay fairly close to the boss so if things do get aggro'd they can be quickly pulled to the boss for AoE. Even better if a healer is WHM because they can gather everything up as it spawns then Holy spam (what I do if I'm not tanking for the group).

As for getting people to come, head to the major cities and shout "Curiosity Killed the Catfish FATE Yanxia 16,11 achievement plus DRK glamour weapon". That gets a lot of attention.