ID unknown hitchhiker (coral? pest?)
 

I have no real way to describe this. It is about an inch round, oval shape. Last time I thoroughly inspected the live rock was about 3 weeks, that particular rock has been in my tank since April. It is in a very shady spot.
It seems to be uniformly attached to the rock (ie no clear base like aiptasia) and doesn't seem to react to touch, movement, or light change.
This particular rock has had problems with hair algae, though the other rocks are fine...
Can anyone ID it?
link to a larger/clearer picture: http://i445.photobucket.com/albums/q...r/unknown1.jpg
http://i445.photobucket.com/albums/q...r/unknown2.jpg
http://i445.photobucket.com/albums/q...r/unknown3.jpg
http://i445.photobucket.com/albums/q...er/unknown.jpg

it looks like a type of sponge to me

I 2nd the sponce. Theres like a bazillion different sponges

Tunicate...possibly? One of the kind that grow in clusters. Sponge or Tunicate, either way it is harmless.

I am not sure what it is, but it is very pretty in my books. If it is not a pest, I wouldn't mind a few more of them!
Though I would be curious to find out exactly what it is.

Very pretty, was what I thought too! :biggrin: But sometimes the worse they are, he he! :wink: Curious to know as well.

Does it react to light or you touching it (use feeding prongs or something in case it is toxic)?

If it does react I'm leaning more towards an anemone. If it doesn't react, and is unchangable for the most part from one day to the next then I vote for sponge/tunicate too.

I used a glasseye dropper (used for feeding frozen food) and gave it a thorough poking - absolutely no reaction, other than being slightly crushed. It was hidden behind some mushrooms and I thought it might have been a majano, but it wasn't until the mushrooms retracted some that I got a clearer look.
But what got me confused is that it doesn't look like the sponges I am used to seeing (not that I have seen many varieties yet). It almost looks 'feathery'.

I was just thinking it looked kinda too feathery to be a sponge, but I have no idea what it actually is. Sort of looks like a feather duster but obviously not without a tube to retract into.

Sorry, I now see you answered my question in your first post, I just didn't read it all... :o

Not an anemone then...but I'm not totally sold on it being a sponge or tunicate either. Try sending your pics to Wet Web Media. http://www.wetwebmedia.com/ click on "Ask WWM". They are quick at replying.