I'm torn here, so I'll give you my opinion, for what it's worth, so take my words as that. Opinion.
Fenner's book is an incredible book and great reference but keep in mind that Fenner wrote this back in 1998 and what was normal practice then may seem a bit radical now. Things change so fast in this hobby it's incredible. That said, I know it's suggested to do these dips on fish and equipment but I don't remember reading about doing that with inverts(not saying it doesn't though, it's been a very long time since I've read the book). Inverts are usually more sensitive and not as tolerant of salinity changes. I mean, after all, we do fw
dips on live rock to rid it of inverts. QT
'ing only is my preferred method. This gives me time to really observe them and time to act if parasites are present. And it is my understanding that fish parasites can not live on inverts since it takes a fish host to thrive. The QT
gives time for any potential parasite that would be a threat to your fish, time to die off. So, not disagreeing with Fenner (he's great, I got to meet him this year at MACNA
), just wanted to give you another option/opinion.