Whats this

[Oscarluva]

These have been growing off the walls, heater, and tubing of my 20 gallon tank what is it. I used to have an anemone in the past but it died. I don't know if that helped but please help!! Also is it harmful.

 

[Bonz]

These have been growing off the walls, heater, and tubing of my 20 gallon tank what is it. I used to have an anemone in the past but it died. I don't know if that helped but please help!! Also is it harmful.

Pineapple sponge. Filter feeder. Its not harmful

 

[Oscarluva]

Pineapple sponge. Filter feeder. Its not harmful

Do they do anything in the outside of the filter. What do they look like when they are bigger. How big do they get.

 

[brian242pa]

they dont get big