Let me back track a little here so we can get a full picture here. Back in mid July, my lawnmore blenny died - and at the time I figured it was because he did not eat. I originally got him to help fight GHA in my tink which he did, but once it was gone he had nothing else to eat and would not touch any food given to him. Well after 4 months of not eating anything, he died.
So I decided to replace him with a long nose butterfly fish. I gave him his freshwter dip before getting into the tank ( he did not like that at all) and put him in. He only lasted 1 week, and the last day he looked like he was covered in ICK but at this point, could have been velvet. So found him dead on day 7.
A few weeks later I added the trigger. Picture of health and never showed any issues and was always swimming up front. 1 week later I decided I wanted to add another trigger, a blue throat trigger. Once he was introduced, the Sargassum did not like it one bit and chased him like crazy...so much so he chased him right into my carpet anemone - so that was a $40 dinner for him.
Since that incident, i did not add any new fish and on 8/30 the Sargassum trigger disappeared and few days later the demise started with all the other fish losses. That's my story in a nutshell.