Sea slug/ sea hare in seaweed

May 21, 2000
From: Jamin Bortz

I was in Galveston, Texas collecting critters from some floating Seaweed when I came across what I call a sea slug. The papers said that all of the seaweed on the beach (tons) was from Bermuda! I guess they had a storm or something. Anyway, the Seaweed is golden brown, it has 1/2 inch leaves with jagged edges, it also has air bladders in the growth structure. It is very firm almost plastic looking alot like what you would see in a pet stores fake plant section. I was collecting shrimp and crabs that matched the seaweed perfectly. The seaweed also has round spots that are small and random, reddish in nature. The shrimp matched the pattern perfectly. The reason for the discription of the algae is that I also found a slug. It is the same color as the seaweed translucent with no shell and can swim with this really cool motion. It has these long thick rabbit ear looking frilly things on the top of its head as well as the back, It is I believe camouflaged to match with the algae. Really neat stuff kinda ugly coloring though. I took a clump of the algae for possible food. Is this enough info to id. could the algae be food, and are sea slugs poisonous.


Bortz, J., 2000 (May 21) Sea slug/ sea hare in seaweed. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Dear Jamin,
Your excellent description of the algae was a good way to identify the slug. Your algae is almost certainly Sargassum, a brown algae which can live floating in the sea and at the entrance to the Caribbean where the currents form giant eddies great 'beds' of floating algae occur in a region called the Sargasso Sea. Amazing animals, as you have described, have evolved to live on or amongst the floating beds of sea weed and by taking on the colour and shape of the algae they are well camouflaged from predators.

The slug you have found is almost certainly Scyllaea pelagica which spends its whole life (except when it is a free-swimming larva), attached to floating seaweed. I have put your message on the Scyllaea pelagica Page. If you have a look above and below your message you will find information, and other messages about this animal. You will also find many beautiful photos, some on the sargassum weed, taken by Anne Dupont in Florida.

To answer your questions. As far as I know they are not poisonous.
They use the algae for a home, not as food. What they eat are hydroids which also live on the algae. Have a look at the hydroid page for some information on what they are.

I hope this answers your questions. Let me know if your animals match the photos ... and again I am very impressed with your description of the algae.

Best wishes,
Bill Rudman.

Rudman, W.B., 2000 (May 21). Comment on Sea slug/ sea hare in seaweed by Jamin Bortz. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from


Scyllaea pelagica

Related messages

  1. Scyllaea pelagica in Miami
    From: Jonathan Cohen, April 9, 2010
  2. Sargassum sea slugs in Gulf of Mexico [1]
    From: Denice Drass, February 22, 2010
  3. Scyllaea pelagica from Nth Carolina
    From: John McChesney, June 15, 2005
  4. Re: Scyllaea pelagica from Virgin Ids, Caribbean
    From: Suzy Hime, May 27, 2005
  5. Scyllaea pelagica from Virgin Ids, Caribbean
    From: Suzy Hime, May 6, 2005
  6. Scyllaea pelagica from Bahamas
    From: Marina Poddubetskaia, March 10, 2004
  7. Scyllaea pelagica in my aquarium
    From: Manuel Marquez, October 17, 2003
  8. Feeding in Scyllaea pelagica
    From: Irina S. Roginskaya., September 10, 2003
  9. Scyllaea pelagica new problem
    From: Ron Velarde, June 30, 2003
  10. Re: Authorship of Scyllaeidae
    From: Henk K. Mienis, June 28, 2003
  11. Authorship of Scyllaeidae?
    From: Gert Lindner, June 21, 2003
  12. Feeding in Scyllaea pelagica
    From: Jason P. Turner, October 21, 2002
  13. Scyllaea pelagica from Turkey
    From: Baki Yokes, October 3, 2002
  14. Scyllaea pelagica from Brac Island, Adriatic sea
    From: Adam Petrusek, October 3, 2002
  15. Radula of Scyllaea pelagica
    From: Bill Rudman, September 14, 2002
  16. Thanks for identifying Scyllaea pelagica
    From: Carrie O'Sullivan, June 13, 2002
  17. Slug? in Sargasso sea weed
    From: Carrie O'Sullivan, June 12, 2002
  18. Re: Seaweed creature from Texas
    From: Alan Titus , June 3, 2001
  19. Seaweed Creature
    From: A Titus, June 1, 2001
  20. Re: Slug on seaweed
    From: Jamin Bortz, May 23, 2000
  21. Scyllaea pelagica from Florida
    From: Anne DuPont, March 9, 2000
  22. Hydroids? on Scyllaea pelagica
    From: Anne DuPont, March 9, 2000
  23. Scyllaea pelagica from Florida
    From: Anne DuPont, December 24, 1999
  24. More on Scyllaea photos
    From: Jim Needham, November 29, 1998
  25. Re: Scyllaea photos
    From: Jim Needham, November 27, 1998
  26. Re: Sargassum sea slug
    From: Jim Needham, November 26, 1998
  27. Sargassum sea slug
    From: Dee Owens, March 21, 1998

Show factsheet and all related messages