Tube things on underside of rock

[Jennduhh]

Hi all,

A short intro: I'm new here, but have had a salt water tank for approximately 2 years. I've only ever had corals, clowns, emerald crabs, coral-banded shrimp, gobys & snails.
That being said, my current tank consists of a clown, an emerald crab, 4 turbo snails & a conch snail, along with a few corals.
The tank is currently without substrate.

Here is my problem:
Recently, as in the last 6 weeks, I've begun to notice something growing on the underside of the main arched-rock in my tank. They began small, as anything does, and I got excited because my leather coral has spawned once before, so I thought that's what these were. I did find it odd that they were on the UNDER side of the rock, away from the light, but thought it may just be something I hadn't experienced before.
Fast forward to now, the...growths...have gotten large enough to see them a little more clearly & I'm 90% certain they're not spawns, as I previously thought. The growths on the right seem to be fuzzy tubes with two little antennae. The growths on the left are just little tunes, but don't seem to be the same as the growths in the right.

I've tried to do some research & have found that the ones on the left may be venetid snails, but am not entirely certain because I've never experienced them before.

TL;DR: Weird growths in tank, don't know what they are. Seems to be 2 different things.

Any help or ideas are greatly appreciated!

First photo is right side.
2nd photo is left side.

Photos are kind fuzzy, my apologies, hard to get clear images zooming in under water.

 

[shakacuz]

pineapple sponge. harmless filter feeder and normal part of a reef.

the last picture could potentially be vermetid snails, but i’ve never seen them white like that. originally i thought feather worms/feather duster but there’s no sign of the feathers

 

[ISpeakForTheSeas]

You’re right - two different things, left side vermetid snails, right side pineapple sponges.

 

[Jennduhh]

Thank you both!
From what I've read, I should try to kill off the vermetid snails. Is that true? & If so, do you have any recommendations?
As for pineapple sponge, I've never heard of such a thing, but will do some research.
I have noticed, today, that there is more of the veiny, white thread like ones, along the underside of another rock and growing along the bottom side of my power head. Theyre weird looking, lol. I'll try to get more pictures of those & hopefully it can be confirmed if they're the same as one of the others.


Thank you for all of your help!

 

[ISpeakForTheSeas]

Thank you both!
From what I've read, I should try to kill off the vermetid snails. Is that true? & If so, do you have any recommendations?
As for pineapple sponge, I've never heard of such a thing, but will do some research.
I have noticed, today, that there is more of the veiny, white thread like ones, along the underside of another rock and growing along the bottom side of my power head. Theyre weird looking, lol. I'll try to get more pictures of those & hopefully it can be confirmed if they're the same as one of the others.


Thank you for all of your help!

Most people would recommend removing the vermetid snails, yes. Lots of different suggestions for how to do so - manual removal, bumblebee snails, glue, injecting vinegar/lemon juice/kalkpaste, coral snow, etc. If you only have a few, then manual removal should work fine, otherwise I’d say to look at some of the methods used on the forum here and try out the ones you think would work best.

Pineapple sponges are harmless filter feeders- they typically boom in population, then bust before eventually going away on their own.

The white ones on the underside of the rock are likely harmless as well - if they become invasive or start growing over corals, those are red flags, but they should be fine/beneficial to keep otherwise.