I have some white sponge like substance growing below my zoas? At first I thought is was part of the colony but now I'm not sure. Any help would be awesome! It looks blue under the led but with a pen light it is white or clear. The "breathing holes" reach pretty far down .
It is probably a form of bread crumb sponge (Halichondria panicea). They are pretty good filter feeders and depending on SP have bacteria that process phosphates in the water. Sponges in general unless they are the boring kind are beneficial water processors that help clean your tank.
Thanks for the response! Wanted to make sure it's not a crazy critter. Getting to close to my zoas so I may have to clear it away. Have a special remedy for yellow sponge?