What are these?

[siege]

So I just spotted these for the first time when I was doing some maintenance in-tank and wound up with one of my lights over my AIO's filter section. It's been a couple of months I guess since the last time I had a good look in there, and I'd not seen them before. There aren't like, a horde of them or anything, but there ARE quite a few. Tunicates of some sort maybe?

 

[york1]

pineapple sponges
nothin bad

 

[siege]

Awesome, I love sponges! I must have accidentally knocked off the crown of one when doing some filter maintenance a while back, because I later saw it floating around the tank, snapped a few pics but then forgot about it, but I'm sure now that's what it was. Wonder that they haven't shown up anywhere in my fuge or main display.

Now, it seems, I need to be a lot more careful mucking about in there.

 

[project1004]

Sponges and filter feeders tent to grow in places where they shouldnt be but…. they do….

sometimes I drop tons of silica to promote sponge growth in the past. I won’t recommend this to any tank that’s not well balanced…. Or you chould get cyno etc. happen to me once. So I stop dosing them.