Are these Coraline Algae?

[peterdinh]

I can't make out what this spike is. It is extremely sharp and growing everywhere in my tank.

 

[NC2WA]

To me, it doesn't appear to. looks like a place where a feather duster would live.

 

[spongebob lover]

i think they're some sort of worm but not sure.
the purple stuff is coraline

 

[Krish]

I agree with Gabby...The pinkish purple stuff is coraline, and the other stringy looking things wants to look like tube worms retracted, but can't say for sure

 

[Curtswearing]

If I had to take a guess, it would be a vermetid snail. They build calcareous tubes and then send out a mucous net to catch particulate matter floating in the water column.

Here's a Macro video of one feeding. http://www.montereybayaquarium.org/video/video_snailnet_feeding_qt.asp

 

[sausage fingers]

Hi,

They are sharp Ive got a hole in my finger that felt like it got cored out as I repositioned some muchrooms on LR, I too have thousands of these just about everywhere but like you Im unsure as to what they are.
Regards

 

[Kurt_Nelson]

Vermetid snail. Totally harmless. Until you stick your finger with one. I've done it myself so I feel your pain.

They're good filter feeders and are fun to watch when they snag a piece of food that's faaaar too big to get in their little hole. They'll cast out mucous nets to get food. They're great fun when you blow off your rock with a turkey baster or powerhead and they all throw out their cobwebs!

 

[ret25yo]

unfortunately they like taking over corals .... these things aggravate the heck out of my corals and every time I break a tube theres a new one the next day.