Nudibranch? Yes, a Dorid: Likely Rostanga species -- 10/2/09
Hi Crew!
<Hello, Nancy, Lynn here today.>
I have an ID question for you.
<My favorite kind!>
I found this little guy on my spider sponge today.
<Beautiful sponge/Parazoanthus combo. Unfortunately, it can be very difficult to keep the supporting sponge alive. Most often, what you see is a gradual decline/disappearance of the sponge that ultimately results in what looks like a melted pile of white Parazoanthus at the base. On the positive side, some hobbyists have been able to keep these. It's not impossible, just very difficult. I'd recommend lots of research!>
I am guessing he is not reef-friendly, or at least sponge-friendly.
<You're right. This is a good example of a Nudibranch species blending in with its food source -- namely, the sponge. What you have is a Dorid Nudibranch, most likely in the genus Rostanga. They prey on mostly orange to red sponges, have upright gills (the posteriorly located feathery structures), and tend to match their particular prey food in color and texture. The rather hairy appearance is due to a covering of caryophyllidia, calcium carbonate/spicule bearing papillae.>
I have quarantined him in a Reef Gently container inside this tank, just in case you say he's ok to keep, I can easily release him back into my tank. He's awful cute,
<He is indeed!>
..and would hate to 'flush" him. Any suggestions on what to do with him?
<I'm sorry to say that this comes down to a choice between keeping either the sponge or the Nudi. If you return the Nudi to the tank, it'll survive but at the cost of the sponge. If you remove the Nudi from its sole food source, it'll slowly starve to death. Unfortunately, one will die either way, so I'll let you make that decision.>
I'm pretty sure it's a Nudibranch, what kind is he??
<It's a Dorid (family Dorididae), most likely in the genus Rostanga. Unfortunately, I can't narrow it down much further without knowing where this little fellow originated. Even then, these Nudi's vary in color and texture so it would still be a guess. Solid ID requires examination of the radula (a tongue-like scraping organ) and rhinophores (the two anteriorly placed antennae). For examples/more information regarding these beautiful little Nudibranchs, please see the individual Rostanga species listed about halfway down this link: http://www.seaslugforum.net/specieslist.cfm
Here's an example (Rostanga bifurcata): http://www.seaslugforum.net/factsheet.cfm?base=rostbifu >
Thanks, Nancy
<You're very welcome. Take care, LynnZ>

Nudibranch or Cucumber? Nudibranch: Likely Tritoniid -- 9/22/09
Hello Crew!
<Hello, Tim!>
Can you identify this marine invertebrate for me please?
<I'll sure try!>
It was a hitchhiker on my liverock. I'm not sure if it's a Nudibranch or a cucumber.
<It looks like a neat little Nudibranch rather than a Cuke/Holothuroid but I can certainly understand the confusion. Both have species with similar body shapes and branched structures around the head/mouth. In the case of Holothuroids, those structures are actually branched oral tentacles used for feeding, and typically number anywhere from 10-30. In comparison, Nudibranchs have oral tentacles along with two 'antennae' called rhinophores. Both tentacles and rhinophores can range in appearance from simple to highly branched/ornate. I think what you have is a Nudibranch in the suborder Dendronotina, family Tritoniidae. Tritoniids feed on soft corals (especially Xenia), so if you have any in your system, I'd remove this little guy. If you'd like to pursue this ID further, please see the following link for a list of species in the above-mentioned family (each is a link with more information/photos): http://www.seaslugforum.net/specieslist.cfm
Start with the genera Marionia and Tritonia. The genus Marionopsis is also a possibility, but not listed (try a Google or other search engine). You might also want to check the family Bornellidae as well (at the above link). There are some similarities around the head but the structures ('cerata') running along either side (down the back) tend to be simpler in shape (less delicate and finely branched).>
Thank you for the help in advance,
<You're very welcome -- that's a neat little critter!>
Tim
<Take care, LynnZ>

Worm? Slug? Nudi? Oh my! 9/20/09
Hi again all, and thanks in advance for all your previous help.
<Hello, and welcome!>
Last week we purchased a Pipe organ coral, on a trip to the coast. Got it home safely, adjusted well, and is beautiful. However we have another hitch hiker, one that I have tried for days to identify. it looked like an
anemone in the middle of the pipe organ, but only able to see little tentacle things waving once the pipe went to bed.
<I see it too!>
Now this evening, when checking out the tank, and turning off lights, we noticed the "hitch hiker" looks like a worm, but kinda different. I've attached pics. Hope someone can help!
Hope it wont hurt any of our sea life. any info would help!
Thanks again!
~Monique
<Looks to be a Nudibranch of the genus Phyllodesmium... Please see the Net re... some are predaceous on animals purposely kept by marine aquarists. Bob Fenner>

Stowaway Nudibranch, Xeniid pred. 04/20/09
Hi crew :D
I recently bought a lovely colony of red sea xenia which was home to a Phyllodesmium hyalinum - the little Nudibranch fell off the colony when it was knocked off the rock work. While this may sound a bit sad I know, the little guy is rather lovely and although I have no wish for it to snaffle my xenia I'd like to know if I can help it to survive, short of putting it back on the xenia colony...
<If it is indeed a Xenia eating Nudibranch, chances are that it needs to eat Xenia in order to survive. However, you might be able to feed it any kind of Xenia. Thus, you might be able to set up a little biotope for it and just feed it xenia frags (if you can find such for cheap). The other option, you could ask your fellow reef aquarists if they have excess Xenia (many reef keepers do-- some even consider the coral a pest at some point).>
after all, I did purchase the animal albeit accidentally!
<I do sympathize, appreciate your sentiment here. I recall a friend of mine who fell so much in love with two beautiful Nudibranchs that hitchhiked on his sun corals, that he forgot about the sun coral and did everything he could to keep the slugs alive by buying dying sun corals from LFSs, just to feed them. Of course, I don't recommend this per se, but I do sympathize with any such love for Nudibranchs. I've also had them as hitch-hikers and always wished I could keep them. However, do know that these animals don't usually live that long (even in the wild).>
Will the Nudibranch ultimately cause the death of the xenia, or will its feeding habits do little more than limit the size of the colony?
<Well, firstly, please do send in a pic so that we can confirm that this is a Xenia eating Nudibranch. Secondly, *one* Nudibranch on a large, fast-growing Xenia colony, might not destroy the colony, but as you say, just keep it "mowed" a bit. The trouble is that the Nudibranch could likely reproduce. Within a short time, you might not just be dealing with one Nudibranch, but many many Nudibranchs... who would likely destroy the colony eventually.>
Many thanks,
Carolyn
<De nada,
Sara M.>

Re: stowaway Nudibranch 04/21/09
Hi Sara,
Many thanks for the reply - have attached a picture of the little guy.
<Wow, great pic! May I ask, what camera did you use? The slug does look like a Phyllodesmium hyalinum. Please see here:
http://www.seaslugforum.net/display.cfm?id=13207
You might even want to write in to this site with your story/pics, since it is noted to be very difficult to find/see in the wild. Thus, maybe Bill Rudman would get a kick out of seeing yours (or at least confirm the ID).>
Carolyn
<Cheers,
Sara M.>

Unidentified Animal: Aeolid Nudibranch: Soft Coral Predator - 4/13/09
Hi Crew -
<Hi there, Kevin>
Can you identify the attached image? I found this beast crawling in my 34G reef tank this morning. Any information you can provide would be greatly appreciated!
<It looks like Phyllodesmium magnum, an Aeolid Nudibranch with a taste for soft corals. It's a beauty, but not something you want to see cruising around your favorite coral! For more information, please see the FAQ's titled: 'Nudibranch and baby? 12/11/08' as well as 'Re: Much more re: Nudibranch and baby?-12/11/08' at this link: http://www.wetwebmedia.com/nudiidf4.htm . >
Thanks,
Kevin
<You're very welcome. Take care, LynnZ>

Re: Finger Leather 04/11/09
Sara M.,
The finger leather mentioned below did continue to show signs of spreading.
We fragged off the bad parts. During the night hours, we discovered what was causing the damage. Attached is a picture.
<Uh oh, looks like trouble!>
Can you confirm that it is a Tritoniopsis?
<I'm no Nudibranch expert, but based on the look of the thing (and where you found it), I would certainly feel safe assuming that that's what this is. Especially after reading the info here:
http://www.seaslugforum.net/factsheet.cfm?base=Triteleg>
We believe that the circle design in the first picture sent was possibly the eggs from this Nudibranch. There are similar pictures on the Sea Slug forum. Would you agree with our assumption?
<Yes... now the real question, how will you get rid of them? I would
suggest quarantining the coral for starters.>Thanks again.
Cindy
<De nada,
Sara M.>

Nudibranch ID help 05/29/09
I can't find a match for this lil critter, the Nudi's body is apprx. 1/4 "long. Thank you, Paul
<Hmm, can you give us any more information? Did you find this little guy on one of your corals? What corals do you have?
Cheers,
Sara M.>

Re: Nudibranch ID Help: Zoanthid Predator -- 5/30/09
<Hello Paul, Lynn here this afternoon.>
I recently set up a new tank, it was a hitchhiker on one of the frags
<Betcha it arrived on the Zoanthids.>
... it was on the glass, if you zoom in it is actually a beautiful Nudi
<Yes, it is.>
..but I have it in a specimen cup till I can find out if it is safe in the tank.
<Good, because it's definitely not safe around your Zoa's.>
It was on the glass not a coral
<Good. What you have looks very much like a notorious Zoanthid eating Nudibranch. They're mostly a brownish/orange and white, but take on the color of the Zoa's they're preying upon. For more information, please see the following link, starting at 'Re: Polyp-feeding Nudibranch' all the way down through the 'Re: Perhaps a gorgonian feeder?' posts: http://www.seaslugforum.net/showall.cfm?base=palyfeed
Terrific photo: http://coralpedia.com/index.php?module=Gallery2&g2_itemId=641
More photos, showing color variation: http://coralpedia.com/index.php?module=Gallery2&g2_itemId=415
I'd keep a close eye on your Zoa's for any indication of predation or signs of additional Nudi's. If you see either, please refer to WWM's FAQ's for removal tips. Just enter Zoanthid Nudibranch in the Google search engine: http://www.wetwebmedia.com/Googlesearch.htm >
..but I have frags of Zoa's, pipe organ, Montipora danae, chalices and good ole GSP in that tank.
<All but the Zoanthids should be in the clear -- at least as far as these particular Nudi's go! Take care, LynnZ>