Can you identify this one?

January 12, 2006
From: Karen Christensen

Bill is this a slug or a flatworm?

I know it's not the best picture in the world, but it's all I have. I  have three of these creatures that came on this piece of coral. They  extend a "fishing line" at night that has several little lines coming off  of the main line. The retract and launch several times as if feeding or "fishing" for food. It takes on the color of its surroundings.

I currently have three of them in my tank with other corals and need to know if they can stay or need to be put in their own tank.

Thank you so much for your assistance.

Karen Christensen
Brooklyn, WI, USA

Christensen, K., 2006 (Jan 12) Can you identify this one?. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Dear Karen,
I guess I should just say I don't know. You don't give me any clues where the animals come from. I guess WI stands for Wisconsin so I guess they aren't from your home state.

I can't see enough detail to be sure what phylum they belong to but your description of them extending a fishing line with little lines off it makes me wonder if you have some benthic ctenophores. If so they should produce a string at each end of the body. Have a look at the photos and messages on the benthic ctenophore Fact Sheet and see if they look similar. There are good photos of some from Turkey with their 'fishing lines' extended.
Best wishes,
Bill Rudman

Rudman, W.B., 2006 (Jan 12). Comment on Can you identify this one? by Karen Christensen. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

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