Hi! I looked through your other thread too, so can say with certainty that your tangs are cute little babies. The desjardini and blue are about a quarter of the size they get. So, agree with everyone else about removing them.
To get rid of the stuff growing around the Zoanthids I would use a soft bristle toothbrush. Looks like a golden algae.
http://www.lionfishlair.com/hitchhikers-guide/ is a great starting point to figure out what it is and how to kill it. Oh and this site
https://www.reefcleaners.org/nuisance-algae-id-guide
The anthias are probably starving. They need to be fed multiple small meals a day. 4+ to be exact. I'm not worried about the number of fish, just overall bioload. You currently have a high bioload for your tank. Not too hard to bring it back down. remove those two huge tangs, don't replace the anthias. See how it looks then.