What is this weird thing

David Engh · Mar 10, 2016

I'm new to the saltwater world an I have a 75g tank with live rock an a few fish. Was looking at my tank the other day an noticed this unusual white algea looking thing just wondering if it's harmful to the tank or just another form of elgea.

It is the cone looking thing hanging from the bottom of the rock.

KJ · Mar 10, 2016

Pineapple sponge Good.

David Engh · Mar 11, 2016

Leave it in there then or get rid of it cause after closer investigation i've noticed them on a few of my rocks.

sbash · Mar 11, 2016

I would leave them. They should be self limiting, however they grew quite heavily in my overflow column in my 65 gallon corner-flow. Either they cannot handle the high flow or something in my tank eats them...