This is what I was thinking as well. Ultimately tore down my previous tank due to these and I think Andrew tore down his 180 as a result of an infestation as well. Definitely to be taken very seriously. Don't mean to be alarmist but they can get out of control quickly and, as far as I have experienced, don't seem to have any effective biological control/predator. Glad to see you had a laser available to take them out. Keep a close eye out for any reappearance and, if possible, you might even consider removing some rock if they seem to be localized. Bummer.