Mushrooms Toxic to Fish?

I just scraped out some rhodactis mushrooms that will never go away! and they spewed all sorts of nasty crap into the water and suddenly I noticed both of my tangs had white bleached out splotches all over them (like they look in the morning sometimes) and their breathing rate was a little elevated. I've already been working on reversing HLLE with my yellow belly blue hippo so she really looks like crap now!
I only had 15 gallons of ro and I whipped up a quick batch of salt, and siphoned out the area where the mushrooms had left crap all over the rocks, I def got some goo out. I'll do another water change asap (I only have  a 75gpd unit). This is awful! Anybody heard of this before?
btw all the other fish seem unaffected (naturally)

 

Do you run carbon?

 

Yup I just put a new cup in yesterday, parameters are all cool;
temp: 78.8
pH: 8.1
NO3

 

If you did this in the tank I could see how it would be affecting them. I would never try fragging any sort of fleshy coral in the tank itself(I know you weren't fragging but similar idea) I have heard horror stories of people doing heavy fragging of zoas and leathers in their tank sense they release some nasty stuff. I would say your on the right track with water changes and running the carbon.

 

yea idk they look totally fine now!

 

NOt AWARE of them doing harm to fish i love them and always looking for more

 

Since they are tangs I would say stress is a factor.