What is this on my rock?

[shaginwagon13]

Never seen this before, anyone know what it is. If I reach in the tank, it retracts itself inside the rock.

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The start to your worst nightmare.

Kill it. Now lol

STAY OFF YOUTUBE I KILLED MY TANK WITH LEMON JUICE THAT I GOT OFF YOUTUBE. The lemon juice de slimed the fish and they all died

I would attribute your loss of life at around 0% to the lemon juice so something else killed your fish. Tons of people have used this method of killing Aiptasia. Also, why do you always type in caps? Relax lol

 

[Daddi0]

I see 2 of them!!

 

[Slarti]

Cheap and easy. I even bought a useless peppermint shrimp that completely ignored my aptasias. It has now become a close friend that I feed by hand and all.
Shoot the thing at the heart with boiling water in a syringe.

Pot luck, is it not. I added one and next morning no sign of the aiptasia...or the shrimp mind you! Shrimp made a shy appearance a few weeks later and we almost up to the hand feeding point. And no aiptasia since!

 

[shaginwagon13]

Pot luck, is it not. I added one and next morning no sign of the aiptasia...or the shrimp mind you! Shrimp made a shy appearance a few weeks later and we almost up to the hand feeding point. And no aiptasia since!

Your lucky.... I have tried the peppermint shrimp route also and no luck for me.

I used a few nudibranch which worked awesome but once they eat them all they starve and die.