i had henniochus in my reef tank (in old tank) ,never bothered my corals. by the way henniochus appriciate and look good in groups of 3or more if you have big tank ,they like it better rather than being alone. from what i have experienced and read most butterflies and other fish do not bother mushroom, mats. they do not like the taste of them. i hope others will give their opinions soon too. good luck. jakleen