What is this?

[ca1ore]

It's not a brittle star, not a hydroid and not a feather worm. An anemone of some kind.

 

[Nailqueencat]

Barnacle?

 

[Dburr1014]

Think it's just down& right of the plug ? the tentacles look too fat for apastia ? Really could use a better pic .

That's is an aptasia. Kill it.

 

[DSC reef]

Looks like an aptasia to me peeking out of a small hole.

 

[Jarhead-CO]

I'm assuming this is what your talking about.

 

[LokiDawg]

I don't think its an aiptasia. It has thick tentacles. Not thin flowy ones like an aiptasia. I'm still waiting for it to come back out after poking it.
I think I found another one that is banded. Not white like that one.

 

[LokiDawg]

It only has 6 tentacles.

 

[LokiDawg]

Or am I wrong that they all look similar to this?
I could be..

 

[Lovemyreef2015]

Definitely looks like a aiptasia.

 

[Jarhead-CO]

Could be majano

 

[LokiDawg]

This is the best i can do far.. And may be a few more days.. I tried to suck him out the hole again..
If it's a bad guy I'll just kill it with kalk.

 

[xxkenny90xx]

Aiptasia can definitely have short thick tenticles like your picture so I'm thinking aiptasia but it's hard to tell

 

[xxkenny90xx]

Here's a similar aiptasia in my tank, he'll be getting some kalk tonight!

 

[vetteguy53081]

Majano. Use syringe and inject either lemon juice or kalk made into a paste into the core of the culprit and watch it melt