Fungus or Parasite Hanging Out of Gill

[ShilohPSU]

Can someone ID this for me? This same thing took out one of my cardinalfish about 3 months ago. I just now noticed that a similar thing is happening to my 4 yr old gold banded maroon clown, which is my favorite fish I would love to know what I'm dealing with so I can treat the problem properly... Someone please help!