White Spiky Ball Part 2

[TinyChocobo]

So... I'm thinking this isn't a sponge as it has slowly moved. Maybe 2 inches in the last 14 days.

I got a decent picture of it.


Also I found this weird green on a live rock. Looks like algae but can't tell what type.

 

[Lionfish Lair]

The green stuff is Neomeris annulata.

And you're right, that's not a sponge. It puzzles me immensely.

 

[TinyChocobo]

It was deep down in the 'tunnel' in the live rock - I think when I inspected the rock I thought it was just part of the rock/dead.

It has been slowly moving to the front - it's almost peeking out now. It looks spiky and moves slowly it appears.

 

[TinyChocobo]

Could it be some kind of urchin or something.

 

[Lionfish Lair]

Any chance of you poking it? If there's a hard surface under there, maybe it's a shell with hydroids.

 

[TinyChocobo]

I'll poke it and report back.

 

[Lionfish Lair]

Your avatar makes me smile, BTW. Just adorable.

 

[TinyChocobo]

That is my oldest son. He is almost 4 now!

 

[TinyChocobo]

Didn't poke it yet. But it's about 1/3 the size it was .....

 

[Lionfish Lair]

But it's about 1/3 the size it was .....

That's not helping the mystery, Mike.

It doesn't look like a tunicate and tunicates don't move.... but they do shrink. Man, I love these puzzles today.

 

[TinyChocobo]

What do you expect will happen when I poke it?

I can get out of bed right now and go do it... Lol.

 

[TinyChocobo]

It feels kinda squishy to the end of my tongs. It didn't seem to do anything when I poked it.

It does look to be back to near its original size before I left earlier today.

 

[Tahoe61]

Some marine sponges are capable of movement, and that looks like one.

Although adult sponges are fundamentally sessile animals, some marine and freshwater species can move across the sea bed at speeds of 1–4 mm (0.039–0.157 in) per day, as a result of amoeba-like movements of pinacocytes and other cells Wikipedia

They are predominantly marine, with the notable exception of the family ... though it has been shown that some are able to move slowly (up to 4 mm per day) within ... It is unknown whether this movement is important for sponge ecology under ...
http://www.ucmp.berkeley.edu/porifera/poriferalh.html

 

[TinyChocobo]

Interesting. I have another in the tank that looks similar but appears to just be getting bigger not moving.

 

[Lionfish Lair]

You got out of bed!!! LOL! You're so sweet. Go back to bed! It's those knobs that are throwing me off. It has to be one, though, doesn't it? But it just doesn't look right!

 

[Lionfish Lair]

Tethya sp?

http://www.habitas.org.uk/marinelife/photo.asp?item=SC0037

 

[TinyChocobo]

It is white not a shade of yellow.