What is it? Do I need to kill it with fire?

[Beau_B]

Stationary, so... Not nudibranch. Not aiptasia. Just a sponge?

Probably nothing, but new tank and all of the things...

Medusa hydroids are present. Pineapple sponges, check. Pods are all over the tank. Those small round white snail things.

 

[Crabs McJones]

Spirorbid worms. Filter feeders. Harmless but can reproduce quickly. Overfeeding or excess nutrients in the tank will cause their populations to skyrocket.

 

[Beau_B]

Thanks, but I didn't mean the worms. I ID'd those from the sticky, and misspoke when saying snails.

That white spiked thing in the middle is my concern! Didn't see it on the list of common pests.

 

[Mastiffsrule]

I would think you’re right, sponge. @Crabs McJones ?

 

[Crabs McJones]

Thanks, but I didn't mean the snails. I ID'd those from the sticky.

That white spiked thing in the middle is my concern! Didn't see it on the list of common pests.

Whoops, my bad. The thing in the center looks like tube sponges. They're very commonly found in zoanthid colonies, but can grow elsewhere

 

[Beau_B]

One other thing while you're here @Crabs McJones

In the chaeto I found a couple of these zoa or paly looking things. I don't have coral in the tank yet so must have come from the algae supplier tank.

 

[Crabs McJones]

One other thing while you're here @Crabs McJones

In the chaeto I found a couple of these zoa or paly looking things. I don't have coral in the tank yet so must have come from the algae supplier tank.

I agree, it does look like a zoanthid polyp that detached and went for a ride.