We think it's a mushroom

[Scott Eiswirth]

These hitchhikers appeared a while back and are growing very rapidly. We like the way they look and would like to keep them but they are now invading the territories of their neighbors. They are about 3" and 2" in diameter and growing fast. Can anybody id these guys for us?

 

[ReeferBatman]

Called 'fuzzy green mushrooms'.

Under blue light they produce a nice green fluorescence.

They can get quite large (enough to eat a 2-3 inch fish if they live long enough)... They have been known to take out fish. I can't find it now, but I've seen a picture of one eating a Banggi Cardinal... heard of others taking out mandarins and gobies/blennys... even a clownfish.



And they are a softie so they will generally outgrow/compete other slower corals (LPS, SPS, etc)... so some consider a 'pest'.

But in a low-care tank they do quite well... I have four in my 30g low-care reef at work...

Because I took them out of my 55g Reef at home to protect the other slower/more expensive corals.

http://www.aquariumdomain.com/viewCoralSpecies.php?coral_id=22

 

[Scott Eiswirth]

Thanks for the help! Do you think they are a big threat to fish? We have a couple of Ocellaris Clownfish that might be in harms way.

 

[Antony2593]

Hey Scott I've never known them to devour fish ,but they are fuzzy greens harmless lol

 

[billsreef]

Those specific mushrooms don't normally eat healthy fish. There are some similar looking ones that do get truly large and on rare occasions manage to take down a hapless fish, but not the variety you've got

 

[psteeleb]

look more like a St Thomas Mushroom (Rhodactis sancti thomae) then the common application of the fuzzy or hairy green mushroom

 

[ssteal]

I have one that has gotten about 6 inches wide and eats pieces of silversides. Blows up like a balloon and surrounds the silverside when placed on it preety wilde

 

[Scott Eiswirth]

sounds like a cool hitchhiker then! Thanks evryone