ID This

[Brian Prestwood]

The ID of this reclusive creature has to be mostly from behavior.

I spotted this last night. The picture below was taken with the PC lights on this morning.

Imagine my surprise when the sponge lining of this hole retracted quickly when I shined a flashlight on it last night.

The opening in the rockwork in the picture below is a little bigger than a quarter. The mottled "sponge" you see inside isn't a sponge at all.

This is the mantle of something that expands out flush over the opening at night leaving what looks like a sponge lined hole. When it is expanded the lining on the opening is about the same diameter as a .50 cent piece. It retracts quickly when I shine a flashlight on it.

When I spotted it last night it was in a hole about 6" away. It moved overnight to another hole and is still visible in the light.

 

[TrappedMetal]

This is a WILD guess and will probably be totally off, but it looks like the texture of an octopus mantle. Give it a gentle poke with feeding tongues or similar and see if it moves?

 

[Octoberfest]

Polyclad Flatworm

Its bad, get it out. This is exactly how I found one in my tank.

 

[charlesr1958]

Without being able to see better details of the creature but going by its lined tubes that it creates, it could be any number of marine worms. I seriously doubt its a flatworm and definetely not an octopus.

Chuck

 

[Octoberfest]

Why do you say its not a polyclad? Looks exactly like what was in my tank, and I honestly thought it was an octopus at first Polyclads can also leave mucus trails

Here are a few pictures to compare the texture and pattern of what you're seeing in the tank.

 

[Brian Prestwood]

Polyclad Flatworm?

Polyclad Flatworm?

When I first saw it I thought it was an octopus to. It isn't but it is colored like one and it moves as fast as a slow moving octopus.

It moved again last night. I found it in yet another hole about 6" away from the last.

As the picture above shows, it forms a lining in the hole. When it expands out of the hole it lines, not covers, the opening. Something flat does make more sense. It could be the business (eating) end of a large cylindrical worm. I doubt it because there simly isn't enough room for the rest of a cylindrical worm in the rock.

I googled a bunch of pictures of polyclad flatworms. I'm pretty sure this is one. Everything I found said they eat worms and crustratceans. That could explain why the peppermint shrimp in my display tank never last more than a few days and the ones in my sump last much longer. I'll keep a close eye on it. Actually, my wife is the night owl. She'll keep an eye on it. The picture below from Ron's website could very well be this. The mottling and flat shape are right. I saw another picture of a juvenile that looked even more like what I see.

 

[charlesr1958]

If there is a flatworm species out there that forms tubes then that would be a totaly new one on me. The creature may have similar coloration/patterns as some of the flatworms shown, but again, forming tubes? Until you can catch it and get some decent photos, this will continue to be a guessing game.

Chuck

 

[cmlloveless]

He never said it forms tubes... Just that it stays in the holes in the rockwork. The hole in the picture looks nothing like a tube to me!! And he said it moved holes! Which means it is most likely not in a tube!

 

[cmlloveless]

After reading the first thread and seeing the picture without going any furthur I would have said it looked like the mantle of a cowerie... Which is very much what the texture of a polyclad flatworm looks like!

 

[charlesr1958]

"Imagine my surprise when the sponge lining of this hole retracted quickly when I shined a flashlight on it last night.

The opening in the rockwork in the picture below is a little bigger than a quarter. The mottled "sponge" you see inside isn't a sponge at all. "

"LINING" implied a tube, be it a hole in the rock or formed by the creature.

Regardless, with the photo shown, there is no way anyone can make an ID on it.

Chuck

 

[Brian Prestwood]

It doesn't form tubes. The picture only shows about half the depth of the hole. The mantle goes about twice as far in. Flattened out I'd guess it is about 2-3" in dia. A cowry with a mantle this big would not be able to fit into a hole this size.