Unknown Growth - ID Please

[cgj]

I bought an assortment of empty shells from a LFS and put them in my tank, to find that out of the ten shells i bought 3 had hermit crabs in them, and one had a little tiny baby aipatsia.
I was facinated by this little thing and now its a bit larger... so its big circular form sticks out of the shell that i have anchored to the side of a piece of live rock. There is only one and it doesnt seem to have reproduced...
Whats so bad about these if i only have one?

 

[perfectdark]

Well if they dont multiply then they are not as bad as the ones that do.. however they are know to be highly aggressive and if let go they can multiply and damage fish and corals. And also wage war on each other which turns physical combat into biological warfare.

 

[dborne3]

Well i went and bought two peppermint shrimp and one emerald crab and they have been busy. Maybe 5 minutes in the tank, one of the shrimp demolished two of the three that i had found. So looks like it will work out alright.

 

[coraldude]

Originally Posted by PerfectDark
Well if they dont multiply then they are not as bad as the ones that do.. however they are know to be highly aggressive and if let go they can multiply and damage fish and corals. And also wage war on each other which turns physical combat into biological warfare.
Eventually they all multiply like crazy.

 

[goingpoor]

KILL KILL KILL
I hate Aiptasia

I HAVE ABOUT 20 OF THEM DARN THINGS I KEEP INJECTING STOP APTASIA IN THEM THEY DIED AND COME RIGHT BACK

IM GOING TO TRY JOES JUICE BECAUSE I THINK MINE HAVE BECOME EMUNED TO STOP APTASIA

 

[ninjamini]

Take kalsawasser and make a thick paste. shut off all flow. Use a dropper to feed the paste to it. Then spackel it over with the paste.
Have airline tubing and fresh salt water ready. Once you do it get ready to create a syphon to suck out all the pieces of the paste that fall off. Yea it will make a mess. Then top off with freash salt water. Be prepared for a alk change. So you will want to test in 12 hours. Be ready for a water chantge.
This works.