Is my hermit snacking on my trachy?

[Dave-T]

This is a Halloween hermit crab (at least it’s supposed to be). They are supposed to be reef safe, but it appears like he’s snacking on the underside of my trachy. Or could he be doing something innocent, and not harming the coral? He is picking at something, and putting it in his mouth.

Thoughts?
Video
Picture:

 

[reeferguy3303]

Crabs are opportunistic feeders , they aren’t 100% reef safe. No way to tell from pictures if it’s eating the coral or something ride