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FAQs about Nudibranch Identification 7

Related Articles: Nudibranchs, Sea Slugs,

Related FAQs: Nudi ID 1, Nudi ID 2, Nudi ID 3, Nudibranch ID 4, Nudibranch ID 5, Nudibranch ID 6, & Nudibranchs 1, Nudibranchs 2, Berghia Nudibranchs, Nudibranch Behavior, Nudibranch Compatibility, Nudibranch Selection, Nudibranch Systems, Nudibranch Feeding, Nudibranch Disease, Nudibranch Reproduction, & Sea Slugs, Marine Snails 1, Marine Snails 2, Marine Snails 3,

Unknown Nudibranch      9/10/17
Can you ID this?
<Mmm; appears to be a Tritoniopsis sp, may be T. elegans... soft coral eaters. Bob Fenner>

help id Nudibranch     7/23/17
Found a dark Nudibranch with white tips on frills and antenna, came as a hitchhiker on red macro algae, less than 1/2 inch long when stretched out.
Would like to know what kind this might be and what it eats.
<My guess is on a Flabellina sp.; perhaps F. exoptata: http://www.wetwebmedia.com/nudibran9.htm
Most Flabellinids eat Hydroids>
So far a hermit crab tried to pinch it and the slug retracted, the hermit looks like it got stung or slimed and backed off cleaning it's pincer arm. Slug moved up a rock and then floated off - drifted in the water current a bit (fortunately not getting sucked into the filter) and landed in back of the tank out of view. Hermit is doing ok now. Attached photo. Any insight to this critter is appreciated, thank you.
<Welcome. Bob Fenner>

Re: help id Nudibranch    7/24/17
Thank you!
<Ah, welcome. BobF>

Reef critter ID, input re comp.       3/20/17
Hi i need help with an id on this creature. I believe it's some sort of Nudibranch just don't know the exact name and whether it is a reef safe or not. Thanks.
Kind regards,
<Is a Nudibranch... don't recognize the species right off; but would keep an eye on... IF it's eating something/s that aren't of interest to you; I'd keep. Bob Fenner>

Nudibranch?    3/2/17
<14 megs? We only ask a few things; one is that folks limit their file sizes...>
I have a 65 gallon reed tank that is flourishing. I have very little problems and all of my corals and inverts are doing very well. The only fish in the tank is a mandarin goby. It is also doing well.
<..."often cited as Tritoniopsis or Tritonia. They commonly come in with leather corals which is their pre.....">

In the last week, my newest addition (had been in tank about 2 weeks with no problems) a 4 inch blushing leather coral, started to fail.
<Bingo; and BINGO was his name oh!>
One of its lobes died off. So, I moved it to a higher light zone. Slowly but surely it died off one lobe at a time. It has completely disappeared as of about 3 days ago. Today, I saw what appears to be a large Nudibranch. I took a picture. In your opinion, do you think this is the culprit? It actually looks a little bit like a blushing leather in coloration. I wonder
if it was smaller before eating and went unnoticed until the leather was gone. Now it is cruising the tank looking for more. Anyway, I can't find a similar picture anywhere to identify this Nudibranch. Have you seen one like this before? Do you know what it is?
<Please read here: http://www.wetwebmedia.com/nudifaqs2.htm
Andy Brenham
<Welcome. Bob Fenner>

Identification please      1/31/17
<Appears to be a SeaSlug (Opisthobranch) of some sort... need to see entire organism. Bob Fenner>
Hi it was suggested to me to ask if you would identify this creature that has suddenly appeared in my Marine tank. I have asked on a couple of groups I'm on but no one seems to know what it is. The last suggestion was a sea hare, but personally I don't think it is. I have attached a photo.
Thank you

re: Identification please      1/31/17
Here are more pics
<Strange.... the sensory processes on the head don't look like rhinophores (of nudi.s), but the girdling underneath the body does.... and the animal lacks dorsal "gills". What are does your live rock hail from? What else with hard structure have you added recently (the last few mo.s)? I've scanned my sea slug ref.s, and the Net and don't see this Gastropod. Oh, and about how big is it?
Bob Fenner>

Re: Identification please      2/1/17
Hi Bob
<Hey Daphne>
The main rock wasn't live, we opted for bleached rock as we had lost everything when our tank crashed. The only live rock I guess would be when we have bought corals,
we have recently had a sun coral from our lps which had been fragged. This hasn't done well in fact the guy from the shop said it looked like
something was eating it. Whether it's this visitor or not I don't know. As regards size when fully stretched out I'd say he is about an inch and a half and goes long and slim, but then he can change and get more flat and broad. He is at the moment climbing around the glass at the front of the tank where he has been most of the day.
<Is it possible that the gills were chewed off here? This looks more like a Nudibranch than anything else. Am going to ask a few friends for their help. Bob Fenner>

Joe Fish I think this is Dermatobranchus... I've seen these come in with corals before... I think it was Knopia or Clavularia they were somewhat regular hitchhikers on
Bob Fenner Thank you Joe. Does appear as such. Will relate w/ credit to you. Cheers.

re: Identification please; and posted to Joe via FB       2/2/17
Thank you both Bob and Joe I will indeed remove from my tank.
<Welcome. Good>
Kind regards
<And you, BobF>

Nudibranch id please       1/28/17
Hello there, I first want to thank you for previous help a long while ago.
My issue was dozens of hermits large and small disappearing completely, shell and all. You (can't remember which crew member in particular) had suggested it sounded like I could have a predacious worm. Soon after I managed to find 2 large fire worms when looking at night. I managed to remove the pair, and haven't lost a crab/snail/shrimp since!
But as for my current question. Yesterday I purchased some corals, specifically a colony of Ricordea yuma, a colony if Zoanthids and a colony of Palys. In addition to the wonderful turbo snail and emerald crab hitchhikers I scored, this morning to my surprise I have a tiny Nudibranch and a small starfish on my glass. The starfish is I believe an Asterina
(grey with 6 arms) but it's at least twice as big as any I've seen in my tank previously.
But my main concern for the moment is the Nudibranch. Of course I'm worried he could be the type that eats Zoanthids, although I'm hoping that the fact that I have found him in the glass is a good sign. Regardless, he is in jail for the moment. I should add that I have now inspected my new Zoas and don't see any eggs as of yet.
I would really like to keep this guy if I can, so please tell me if you think he is a good Nudi or a bad Nudi.
<Mmm; appears to be a Aeolid... do consume Cnidarians... often look a lot like their prey>

I hope these photos are clear enough to get a good identification. He is about a quarter inch long.
I would also like to know, if he does end up being a Zoanthid eating Nudibranch, is that what they eat exclusively?
<Don't know; but too likely so. See the Net w/ the family name...>

Rather than killing him I would like to set up a nano tank to keep him and any other future questionable hitchhikers but if he will die without Zoanthids I guess I have no choice.
Thanks in advance!
<Welcome. Bob Fenner>

Hi Crew!
Still cycling my 28 nano but saw my first official hitchhiker today...guessing it is some sort of Nudibranch! :)
<Ah yes.... do you have Cnidarians present? Do see WWM re Nudibranch ID. Bob Fenner>
Fwd: Nudibranch?

By the way, no Zoanthids in my tank, still cycling. There looked like
there were some tiny remnants of a yellow sponge that matched his tentacle coloring--wonder if that was his food?
<... possibly; though I doubt this. Likely some other stinging-celled life on your live rock is supporting this/these for now.>
Don't want a pest, but if he just eats sponges or won't like explode into a population of nudis then I'll let him wander in my tank.
<Likely what I would do as well at this juncture. BobF>

Re: Nudibranch?      12/31/15
So last night I searched the tank with a light and saw something yellow, matching my little Nudibranch friend. Seems you were absolutely right, seems to be some kind of coral?
<This looks like a sponge to me... no polyps; but a few osculae in view>
I'm not even sure if it is still alive?
<Appears to be>
Sort of bummed my Nudibranch friend is a coral muncher!
<Mmm; night not be. Most consume hydrozoans....>
Anyway, thought
you'd like to see the puzzle come together, happy New Year! :)
<And you! BobF>

Aeolid Nudibranch ID?      9/14/15
Dear Sirs,
A friend on a reef forum has suggested you may be able to identify these slugs I have been finding in my aquarium. She suggests they might be either *Aeolidiopsis** ransoni* or a *A. harrietae*.
<My money is on the latter. A fave ref. (Bill Rudman)
I'm attaching a
number of photographs of a number of different animals. All have been found on or very close to Zoanthid soft corals within my reef aquarium.
<Do consume Palythoa>

The largest animal is around 10mm long with the small ones being 2-3mm I look forward to hearing from you.
Best wishes,
<Thank you for sending this along. Bob Fenner>

Re: Aeolid Nudibranch ID?     9/15/15
Dear Bob,
<Hey Dave>
Many thanks for the identification. I'm busy removing them off my Zoanthids...
<Ah yes; I would>
Best wishes,
<And you; BobF>

Aeolid Nudibranch ID?         6/18/15
Hello crew!
I have been successful for years due to wealth of information this site has to offer. Thank you for your time and service! Now I am hoping I can get a verification of what I think I have learned after reading lots of links here.
I have had a pistol shrimp / Goby combo for the last three years. This year we slowly started adding corals to their tank. I have diligently QT everything we bought and everything has been cleared and in the display tank. Well, (yep here it is...) except some rock rubble that I bought last week for the pistol shrimp (he gets so excited about new rocks outside his
door) from my local saltwater retailer's live rock bin.
Two days later I saw this guy on the glass, he was about the size of a grain of rice, and I removed him from the tank (picture attached taken with a magnifying glass). Two days after that my only piece of Montipora has batches of these same things around the base.
<Trouble; are Montipora eaters. Need to isolate, and likely dip/bath all incoming corals to avoid such undesirable hitchhikers>
The Montipora is now in a hospital tank and manual siphoning of the Nudibranch has begun. I believe from what I have read that these are Aeolid Nudibranch but if you can verify I could not find many definitive pictures on the link for these (http://www.wetwebmedia.com/MontiNudiF.htm).
I just want to make sure I have the right plan of attack by making sure I am reading about the right thing. I have not seen a single one of these Nudibranch on any other SPS or LPS I have (although I will continue to check daily).
Thank you!
<There are a few approaches... I'd be reading, and pronto. Bob Fenner>

What is this?       1/30/15
<Ahh; Tritoniopsis; a soft-coral feeding Nudibranch. Bob Fenner>


Orange and Yellow Nudibranch... Iatrogenic troubles... incomp.       5/18/14
Hi, I have a question regarding a Nudibranch I purchased last month. I have included a picture of him. Beautiful specimen, very interesting to watch. I bought him from my LFS, which is normally pretty solid. The Nudi came in as an extra.
<A bane of the trade... go ahead>

I saw him and asked about him. I was told they were not given a name, and as such could not sell it to me because they were not sure what it ate.
<I do like their honesty here>

The next week I came in and was informed that they had indentified the Nudi. I was furnished with a picture in a book, which identified the Nudi and said it ate only live red sponge.
<Mmmm; doubtful>

The picture looked exactly like the Nudi, so I went and bought a red sponge
<... there are many different types of reddish poriferans. Some are NO fun>

and then came and got the Nudi. I do not recall what the Nudi was called, but I can find out.
Well, the Nudi didn't ever touch the red sponge. Since I've never had a Nudi(other than lettuce)
<And these aren't Nudibranchs... see WWM re Elysia>

I assumed he was eating and I was just not catching him. I came home last night and the Nudi was not moving, just sitting in the corner...not usual for the specimen from what I've witnessed. I also noticed my livestock in the tank not acting normal, so I kept and eye on the tank. This morning I woke up and the Nudi had not moved, so I picked him up and smelled him.
Dead. So I flushed him and tested the water.
Parameters are as follows.
Mg-I don't have a test

I know my trates a high, but this is a biocube with many anenomes

and some sun corals. Only 3 fish, a potters angel
<Misplaced here>
and a pair of gold striped maroon clowns.
<These two too>

I struggle to keep the trates around 40, so 80 is high even for what I'm used to seeing. All my anenomes were sucked up and not behaving normally.
<Opisthobranchs can definitely be trouble when they die, dissolve in small volumes>

Fish did not seem to be affected. I also have a basket starfish in there, which fell from his favorite spot and died. So I immediately did a 75% water change. The livestock is starting to do better(6 hours since water
change). The only casualty seems to be the starfish :(.
Anyway, my question is....can you help me identify this Nudi and what he eats?
<Not one I've see, photographed... and too lazy to get out my references... see the works of David
Behrens, or spend a few hours on "SeaSlug Forum">
Is there anything else I can do to ease the stress on my tank from the dying Nudi?
<Read on WWM re... can you see, use the search tool, indices?  Nudibranch compatibility...>
Thanks for your help!
<Welcome. Bob Fenner>


Yes, and ID question.... sorry     3/27/13
You California guys have much info on this????
<What is that? Renilla? BobF>        

Identification attempt for 3/27/13 creature
*Yes, and ID question.... sorry     3/27/13*

You California guys have much info on this????
<What is that? Renilla? BobF>
hello! I thought I might offer a guess as to what this creature might be. My guess is that this is a Chiton, maybe
Cryptochiton stelleri; the colours and shape seem to match.
<<Ah yes Emilie. Please see LynnZ's input below. BobF>>
Hey Bob!  I think the critter in question is Cryptochiton stelleri, aka the Gumboot Chiton.  Here's a link with a photo/info:
http://seanet.stanford.edu/OtherMolluscs/#Cryptochiton_stelleri  .  Hope that helps!
Take care,

Nudibranch ID    1/11/13
Can you ID the attached pic of a Nudibranch? I believe it is the type that eats Zoanthids, but I see no damage to any of my colonies and I found this guy in the sump. Thanks!
<Mmm, yes... appears to be an Aeolid... do place the string:
"Aeolid predators of Zoanthids"
in your search tool and read re. Bob Fenner>

cropped and enhanced
Re: Nudibranch ID    1/11/13
<Welcome Van. BobF>

Hermit Crab and Nudibranch: Clibanarius cruentatus and Aeolidiella alba, IDs, comp. – 11/13/12
> Hi,
> <Hello, Lynn here this morning.>
> I recently brought 2 'Mexican algae hermit crabs' that were supposed to be reef safe, one of them I cannot identify the species... Any idea?
> <Yep, it appears to be Clibanarius cruentatus, aka the “Spotted Black Hermit crab”, which is in the family Diogenidae (left-handed hermits). Whether this species is completely “reef-safe” depends on your definition of the term. Hermits are typically omnivorous but can have tendencies toward being either more herbivorous or carnivorous.  What's important is that if/when their preferred food dwindles, and they get hungry enough, they will likely “sample” whatever else is available. Bottom line: keep an eye on any and all hermits - even those labeled as reef-safe, algae-eaters, or herbivores.  That is, watch what they tend to eat, make sure they have enough, and monitor for any damage to livestock.  It’s a good idea to supplement their food with meaty bits of marine origin, sinking pellets, and/or bits of Nori (dried seaweed sheets).  Please see the following link for more information and photos regarding Clibanarius cruentatus: http://www.wildsingapore.com/wildfacts/crustacea/othercrust/anomura/hermit/spottedblack.htm 
> More information on hermits here: http://www.wetwebmedia.com/marine/inverts/arthropoda/crabs/hermitcrabs.htm?h=  >
> Also found a Nudibranch on my live rock which I cannot identify.  He doesn't seem to have touched my corals.
> <That’s good to “hear”/read but do keep an eye on them as sometimes the damage isn't immediately apparent. You have what appears to be a species known as Aeolidiella alba (family Aeolidiidae). If you can get a close look at the base of the rhinophores (the knobby-looking appendages just behind the head), you should see either a fine reddish line, ring, or splotch (see photos at links below for comparison). Also reported, is this species’ odd appearance during locomotion as it “waves” or “jerks” its cerata (appendages along the back) back and forth.  Unfortunately, I wasn’t able to locate any information regarding the animal’s diet, but rest assured, it’s a carnivorous predator. These Nudibranchs tend to hitchhike on or near their food source so if your individual arrived on a recent coral addition, I’d remove it asap, and keep an eye out for others.
> Please see the following links for photos and more information:  http://www.seaslugforum.net/showall/aeolalba
> http://seaslugsofhawaii.com/species/Aeolidiella-alba-a.html 
> More information on Aeolids here: http://www.wetwebmedia.com/MolluscPIX/Gastropods/Opistobranchs%20Sea%20Slugs/Nudibranchs/nudibran5.htm?h= 
> Take care,
> -Lynn Z>

Re: Hermit Crab and Nudibranch: Clibanarius cruentatus and Aeolidiella alba – 11/13/12
<You’re very welcome.>
..he came with my live rock which had 1 single Zoa and a single mushroom as hitchhikers. I let the rock cycle and he is still alive and the Zoa and mushroom are fine so I don't know what he could have been eating to live.
<Based on what seems to be the common theme within this family, I’d say a Cnidarian of some sort. Every Aeolidiella species that I was able to find diet-related information regarding, listed one/several varieties of anemone as being their prey of choice. Interestingly enough, other genera within the family (Aeolidiidae) listed hydroids and Palythoa in addition to anemones so that adds to the list of possibilities. Whatever the prey, it’s possible that there may still be some small/hidden individuals left that are sustaining your Nudi. On the flipside, if it has already gone through the food supply, you will likely see the animal roaming about the tank for a short while, then one day it’ll just disappear. Take care, Lynn Z>
Re: Ahh, excellent as always. B – 11/13/12

Thanks Bob, it was a pleasant surprise to see that query in the inbox this morning.  I check in every day, looking for ID's but must be missing them.  
At any rate, it's always a pleasure to see what neat little critters end up in people's systems!
Take care and thanks again,

Nudibranch ID – 4/19/12
Hi crew.
<Hi there, Lynn here this evening.>
 Hopefully just a quick one for you.
<Heheee, I wish! That happens only occasionally when it comes to Nudibranchs.  There are simply too many species and too many variations, etc., to have them all available in my head for quick recall.>
Can any of you correctly ID this Nudibranch species? It's baffling us and we have scoured everywhere trying to look for something that it resembles. I know it is difficult to see from the attached picture but it does have a crown
<I'm not sure what you mean by “crown”.>
…and rhinophores as not to be confused with an Aglajidae.
<Is there any possibility of procuring and sending along a few more photos – or at least one that’s larger, showing more detail?  Unfortunately, I can’t see enough in the current one to narrow the ID with any real certainty.  Right now, I’m not sure if what you have is a sea slug, Nudibranch, or even a flatworm of some sort.  Offhand, I’d say it looks a lot like a Nudibranch in the family Dorididae or Chromodorididae.  The general shape of the body and simple (as opposed to branched) rhinophores are on target but I don’t/can’t see any gills that are typical of these families.  The gills, when extended, appear as a ring of feathery appendages extending from the posterior dorsal/top surface of the animal).  Please see the following links for an example of a species in each family (note the degree of variation in color/pattern):
Dorididae: http://www.seaslugforum.net/showall/apheanti
Chromodorididae:  http://www.seaslugforum.net/showall/hypsinfu 
If your animal does have the aforementioned gills, and you have the time, you might try looking through the species list at the following link, starting with the two families listed above, and see if you can find a match: http://www.seaslugforum.net/specieslist.htm 
If the animal does not have those gills, and you’d still like to pursue an ID, do send along another photo or two and we’ll try again.  I’d also need more information, such as size, where the animal originated, whether you’ve noticed it feeding on anything in particular, and any other descriptions or information that might be pertinent/helpful but not necessarily visible in the photo.>
Many thanks once again
<You’re very welcome.  Take care, Lynn Z>

Re: Nudibranch ID: Hypselodoris spp. - 4/20/12
Hi Lynn
<Hi Si>
Thanks so much for the speedy response and especially the links.
<You’re most welcome.>
We have come to the conclusion that it is definitely Hypselodoris infucata.
<Yay, we have a winner!>
It is exactly like the attached image.  Although it is very small so most likely to be a juvenile. What is their diet as I've been led to believe they feed on sponges
<They do indeed.  Their preferred prey is reported to be the species Dysidea fragilis.>
(Is it reef safe)
<Depends on your definition, but everything should be safe except for the sponges.>
...and also what is the likelihood of it surviving in an aquarium?
<Unfortunately, not much (long term), unless the sponge variety that it feeds on is plentiful, or able to regenerate itself faster than it can be consumed.  Right now, it sounds like the little Nudi is fairly small so there may be enough food around to sustain it.  As it grows, however, things get a bit dicey.  This species reportedly gets up to about 55mm, or around 2” in length, so as its size increases, so will its appetite.  More than likely, you’ll see the Nudi wandering around for a while then it will simply disappear.> 
Thanks again
<It was a pleasure, Si.>
<Take care, Lynn Z>

Mystery Invert 2/19/12
Hello WWM Crew,
I am sending you four jpegs of what I believe is some sort of Nudibranch.
I don't know if it's a Nudibranch or a slug.
<All Nudibranchs are sea slugs, but not vice versa. This is a member of the genus Phyllodesmium>
It was under a large hairy mushroom and I thought is was some sort of tube anemone. I lifted up the mushroom to get a better look at it, and some of the "cerata" (hope that's correct venacular),
came off the body. I used my high tech turkey baster and removed it from the live rock. More of the cerata came off.
The cerata are kind of flat, and moved back and forth after they detached from the body. I thought they may have been flukes or some sort of salt water leech. I wasn't sure it was a Nudibranch until after I watched and saw that it had a distinct body and oral tentacles. Anyway, I have removed it from my aquarium because I don't know what it is and it appeared to be snacking on my mushroom.
<Could be. May need to be removed>
I really enjoy finding things in my aquarium, especially things I've never seen before. I also took a video of it. I searched WWM and the Internet for information and pictures of organisms similar to this Nudibranch. I realize you are inundated with requests for identifying organisms so any information you could provide would be appreciated.
Best Regards,
<And you, Bob Fenner>

Re: Need help with id 11/21/11
Sorry about that, I was doing a Google image search. Here is a picture of the Nudibranchs in question.
<Neat! Looks like a member of the Eubranchidae, genus Eubranchus... and a great mimic of the green algae Neomeris (annulata)!>
There are two references on the page, and the information contained isn't helping. The two are Nudibranch 8/16/07 Nudibranch, Sea Cucumber or Sea Slug? Aeolid Nudibranch 6/18/07
<Is this a close enough guess for you? Need to remove of course if it is doing too much (predatory) damage. Cheers, Bob Fenner>

Re: Need help with id 11/22/11
What do you mean by predatory damage?
<? What this species of naked gill slug eats, chews on>
What is it that they eat or do?
Is it reef safe?
<? Why are you writing instead of reading where you were referred to? B>
Re: Need help with id 11/22/11
Oops! Didn't paste a referral. See here:
and the linked files above. B

Re: More Re: Need help with id, Nudibranch 11/22/11
I am sorry, but after 7 hours of reading and trying to figure out what this is, I have no idea. I looked at the species you mentioned and there is nothing that looks like it. Can you just tell me if it is good or bad?
<... likely "bad" as in what is this animal eating here? I would remove it if it is obviously doing too much damage. B>

Nudibranch, ID 11/11/11
Can you identify this type of Nudibranch for me? I have not been able to find it myself. Also, is it safe for my reef tank? I have only seen it twice, just on the glass.
<Mmm, no... this image is too blurry, poorly resolved. Need a clear image of the dorsal surface>
<It may not be harmful; you'll have to keep an eye on what it may be feeding on. Read here:
and the linked files above. Bob Fenner>

Nudibranch Identification 10/20/11
Hello WWM Crew!
<Hello Jessica>
First let me thank you for your invaluable service. I have found the answers to virtually all of my reef aquarium questions (and they are plentiful!) on your site, and have you to thank for my thriving Nano mixed reef. On to the question. I recently had my LFS order me a lettuce slug.
Expecting to see an Elysia crispata, I was surprised when this creature was in the bag. I called the LFS and had them check their manifest, and he was listed as an Elysia sp., but I don't believe it. I believe it is a Nudibranch rather than a slug, but after much searching on seaslugforum, I have not been able to identify this guy. He is about 2 inches long, and I fear that he is not the harmless herbivore that I was hoping for. I know many of these guys have specialized diets, so I fear for his survival as well as that of my tank if he is toxic. He is currently in quarantine until I figure out what he is. Your assistance is greatly appreciated!
<Since there are a gazillion species of Nudis, I suggest going here to find a match.
I just do not have the time to go through all these.
Bob may have seen in the wild and/or may know and will input here if so.>
<You're welcome. James (Salty Dog)>

Re Nudibranch Identification 10/20/11- 10/21/22
Thank you for the link.
<You're welcome.>
I was able to determine that this guy is a Ceratosoma sinuatum, a sponge-eating species of Nudibranch with no chance of survival in my tank.
I immediately found two other references to this Nudi being sold, as mine was, as an Elysia crispata, or lettuce slug, so I thought it might be a service to other perplexed readers to post the ID. The distinguishing features are the white speckles both on the "antennae" and the feathery gill cluster on his back, the three "humps" on his back, the tallest being nearest to the gills, and the broad lobes edging the mantle. They come in many color variations, but usually have a green background with yellow and blue speckles. At least one person reported a distressed one oozing a white discharge, so I have some concern about toxicity. Hopefully this helps someone else out, although it would be better if no more of these poor creatures are mis-collected!
<Thank you for this follow up, Jessica.>
Thanks again,
<You're welcome. James (Salty Dog)>

Nudibranch? -- 02/04/11
Hey guys! As always, you guys rock!
<And roll!>
I need some help identifying a Nudibranch/worm/slug... I've never seen this one before. Any ideas?
<Looks to be an Aphroditid: http://en.wikipedia.org/wiki/Sea_mouse>
John Patten
Tampa Reef Marine Management Services, LLC
<Welcome! Bob Fenner>

Re: Nudibranch? -- 02/04/11
Should I discard it? I found it in a Nano reef.
Thanks again!
<... depends on what you have, what you're trying to do w/ "it"... See the Net re the life habits of this Errantiate Polychaete family. B><<Don't tell John... but mainly this family consumes other worms... Nereids principally, Shhhh>>
ID Please: Nudibranch, Possibly Melibe viridis -- 8/5/10
Dear WWM Crew,
<Hello James, Lynn here today.>
I received this as a freebie from my LFS in Nagasaki, Japan. I have no idea what it is and was wondering if you might shed some light.
<What you have is a neat little Nudibranch in the genus Melibe, family Tethydidae. Without knowing where it originated, I can only give you a best guess as to species. It looks most like Melibe viridis, a potentially large (up to 12cm/4.72' long) species with a taste for crustaceans. For more information/photos, please see the following link: http://www.seaslugforum.net/showall/meliviri >
It is 8 cm long. I've attached a picture as it looks like something you'd find under a microscope.
<Great photo!>
Whatever it is, I'm not letting it near my H. kelloggi until I know it's safe.
<Well, personally, I wouldn't add this to a seahorse tank. Although Melibe viridis is a crawler that mainly eats crustaceans, it can get fairly large. I'm not sure how large your H. kelloggi individual is but I wouldn't exclude the possibility of the Nudibranch coming across it while it's resting, trapping, and ingesting it.>
James Miller
Okayama, Japan
<Take care, Lynn Z. >
Mysterious Creature 8/5/10
Hello Lynn, hello Bob,
There's a great mysterious creature question in the marine inbox. I have NO idea at all what it is. Can't wait to hear what you think.
Cheers, Neale
Re: Mysterious Creature
Thanks Neale,
I've seen one of these odd-looking creatures before. It's a Nudibranch in the genus Melibe, possibly Melibe minuta - http://www.seaslugforum.net/meliminu.htm
I just woke up, so as soon as I get some coffee in me, I'll get the query written and sent on its way.
Take care and thanks again,
-Lynn The ones I've seen in N.E. Sulawesi, suck up/vacuum muck... will attach pix. B
Yikes! What I still have a hard time grasping is how it can consume sizable crabs without getting nipped into letting go, or shredded. That oral "veil" must be a lot tougher than it looks.
Some are outright surprisingly LARGE! Have "come across" species, specimens over a foot in length. B Wow, how neat is that? Great shots, Bob!
-Lynn Mmm, well, wrong lens... 105 mm... and too short a focal depth/width...
<Well, I guess that just shows how much I know...or don't know! I thought they looked great. It's just such a neat-looking creature. It looks like a miniature version of some space monster from the original Star Trek series.>
but neat animal.
It had some commensal Hippolytid shrimps "riding shotgun" on it, neat as sunshine. B
<Oh wow, that is neat. I guess they fed on whatever was stirred up/dislodged as the Nudi foraged? See, this is why I love ID work so much. I'm not able to see all the neat things you regularly observe in person while diving, but this way I still get to "discover", albeit vicariously, some unbelievably neat creatures. Thanks for sharing your photos..take care, Lynn>
<Welcome Lynn. B>

Sea Slug ID: Likely Tritoniid Nudibranch - 5/23/10
Hi Bob, et al,
<Hello Nick, Lynn here tonight.>
Had a problem with one of my corals recently,
..lifted it up to take some photos and found these two slugs below
<Not good>
(Please excuse the Aiptasia, that's another headache).
<Yep, they definitely can be a headache!>
I believe they are the culprits for the nasty damage to the coral, coming out to eat it at night.
<If the damage was done to soft corals, you'd be right. What you have looks very much like a couple of Nudibranchs in the family Tritoniidae (Suborder: Dendronotina). Nudi's in this family prey on soft corals, hydroids, sea pens, and Gorgonians. I'd recommend removing any and all individuals (as well as any egg masses) with something like a turkey baster. Quarantining the corals would be a good idea, if possible. If not, keep checking the corals (especially at night) and remove every Nudi you see. Please see the following link for an example of a common tropical specie: http://www.seaslugforum.net/showall/triteleg >
Are you able to help with identification, and confirm they would be eating it?
<Well, it would help to know what kind of corals were being preyed upon, but since those look like Tritoniids, I'm guessing they're softies. For more photos of species in this family, please see the following link. Tritoniidae starts about 3/4 way down the page. Each species is a link to an information page with photos. http://www.seaslugforum.net/specieslist.cfm >
I've tried www.nudipixel.net but can't seem to find a match.
<There are an awful lot of Nudibranchs out there!>
Many thanks for your help.
<You're very welcome.>
<Take care.>
<Lynn Z>

Re: Sea Slug ID: Likely Tritoniid Nudibranch, now Nephtheid - 5/24/10
Hi Lynn,
<Hi Nick!>
Thank you so much (I must also say WWM is brilliant)
<You're very welcome and thank you!>
It is indeed a soft coral, and the only coral I currently have - I can't remember its name now, could it be a Nephthea?
<Well, coral ID's aren't exactly my forte, but that does indeed look like something in the family Nephtheidae (order: Alcyonacea). Unfortunately, Tritoniids love to eat Alcyonaceans.>
There are some photos attached if that helps.
<It certainly does, thank you.>
I wasn't sure I was able to keep corals alive in my tank, now it looks like they might have just been eating them.
<Likely so>
I think you are right, it may have been the white vs. orange that made me miss the pictures.
<I can certainly understand. That particular species varies from white, to orange to a reddish orange but if you don't know that, you can easily dismiss it as a candidate. I've done the same thing myself a time or twenty!>
On closer inspection, it indeed looks like they have laid eggs all over the base of the coral,
<Yikes! I'd hoped that wasn't what I was seeing in one of the previous photos.>
I thought about using a freshwater dip, but I believe I read on your site that the freshwater dip could kill the coral,
<Yep, corals do not like freshwater dips.>
..so will probably go with gently scrubbing them off in a bucket of tank water.
<Sounds good. Definitely get rid of those eggs and keep an eye out for more Nudi's.>
<Take care>
<Lynn Z>

Identify 4/3/10
Was hoping you might be able to help identify the little critter pictured
here. My nephew caught it in a bucket on Miami Beach. Thanks
Mario Barroso
<Is Glaucus..., an Aeolid Nudibranch; likely G. atlanticus:
Bob Fenner>

Help With A Slug ID? Likely Dendrodoris nigra or fumata - 3/12/10
Hi WWM crew!
<Hi Adam, Lynn here today!>
I'm hoping you can help me with an ID on something that has apparently hitchhiked its way in to my 90g reef tank.
I will attach the two best pictures I have of it in this e-mail. I have to apologize for the iPhone photo quality but wouldn't it be my luck that when something cool and unexpected appeared, my big camera was sitting on my desk at work.
<Murphy's Law strikes again!>
It was about 1.5 inches long, half an inch across and looked very much like a slug with a ruffled skirt of tissue all the way around its body. It has two antennae
..and what looks like..a wilted flower the part of its body that I assume is its anus or maybe gills.
The pictures make it look black, but under the halide lights of my aquarium, it was the deepest royal blue I have ever seen on an animal. It had two rows of tiny white dots down its back (I played around with the gamma, white balance and exposure on these pics in PS so you can see the dots) and white dots on the tips of its antennae. I was a little shocked to see something that large and delicate pop up unexpectedly in my tank which has been up and running now for 6 months and my initial reaction after "wow that's pretty" was concern, as I know that some sea slugs/Nudibranchs can be quite dangerous in a reef aquarium.
<Yep, Nudibranchs in particular can be a real problem sometimes.>
Last month something started eating the polyps on one of my largest Acropora colonies in the night
<Uh-oh. Take a good look at the colony at night and watch for the usual suspects: Asterina stars, other Nudibranchs, crabs, coral-eating snails, a large Fireworm, flatworms, etc. Basically, look for anything on or near the coral.>
..and I thought I had identified the culprit to be a small, hair covered, mucous blowing crab that I removed,
<Heheee! That sounds like the person that sat behind me in Avatar a couple of weeks ago! Seriously though, the crab could well have been the culprit. Just keep an eye out for further signs of predation, just in case.>
..but I didn't know I had something as odd as a sea slug in my tank at the time. From the looks of its mouth parts which I got a peek at when it pressed against the glass, it looks like an algae eater but I've also heard that some sea slugs can be quite toxic.
<Yes indeed. There's a Sea Hare/Aplysiid from around Australia that's been responsible for quite a few dog deaths. Apparently the dogs find them washed up on the beach, eat them, and sadly, it's game over.>
I've been pouring through the sea slug forum species list at http://www.seaslugforum.net/specieslist.cfm,
<Love this site>
..but I'm afraid in my totally naive state I don't even know what family or Superfamily I should be looking in. Some members of the Onchidorididae family appear to have the right body shape, but I don't know how diagnostic that is.
<It all helps, believe me. By the way, kudos to you for even beginning to look through that long list of species!>
Any suggestions on where I should be looking
<Yes, take a look at the Nudibranch species Dendrodoris nigra and Dendrodoris fumata (Suborder: Doridina, Family: Dendrodorididae). They're common, tropical Nudibranchs from the Indo-West Pacific that feed exclusively on sponges and are often mistaken for each other. Both have white-tipped rhinophores and are mostly black as adults although they can appear bluish under certain lighting. For more information on these two beauties, please see the following links, starting with the FAQ titled 'Flatworm Identification: Actually, A Nudibranch: Dendrodoris nigra or fumata -- 2/17/10' here: http://www.wetwebmedia.com/nudicompfaqs.htm
Dendrodoris nigra: http://www.seaslugforum.net/showall/dendnigr
Dendrodoris fumata: http://www.seaslugforum.net/showall/dendfuma >
..or if this is dangerous?
<It is to your resident sponges. Other than that, it doesn't pose much threat to the system as a whole. The good news is that it's a fairly small Nudi in a large volume of water so any potential toxins released upon death should have negligible impact.>
I would prefer to not remove it as it's quite beautiful,
<It is indeed.>
..but considering how long it took to find it (and believe me I spend more time than I should staring in to my tank)
<Me too!>
..I don't even know if I'll ever see it again.
<You might not. It happens that way sometimes.>
Thanks again for your invaluable assistance,
<You're most welcome.>
Adam LeClair
<Take care, Lynn Zurik>

Nudibranch ID Link -- 02/08/10
Hi Guys/gals,
FWIW, I came across this site today and found it pretty interesting, especially with over 22,000 Nudibranch photos.
<More Nudi/es than many porn sites! B>

Nudibranch Photos to Share: Likely Tritoniid -- 11/28/09
<Hello Lianne, Lynn here today.>
You are always sharing with us, thought you might enjoy these photos.
<Thank you!>
This Nudibranch was sold to us as a small "sea hare" (hare, hare, hare),
<Heeeee! Although it does bear a superficial resemblance to the Blue-Ring Sea Hare (Stylocheilus striatus), that's not what it is. Your little critter looks like a Nudibranch in the suborder Dendronotina, family Tritoniidae. These creatures eat soft corals, gorgonians, sea pens and possibly hydroids, have distinctive 'pulpit' shaped rhinophores (sensory tentacles on the head), as well as a number of branched cerata/outgrowths that run the length of the body on either side. They also have what's called an 'oral veil', a multi-branched digitate flap that overhangs the mouth and can be seen in your photos. This is used to detect/locate open polyps. Unfortunately, I can't tell you what specie this is, but apparently the blue spots I see on your individual are fairly common in many of the Indo-West Pacific varieties. 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). Be sure to note the degree of color variation within each specie: http://www.seaslugforum.net/specieslist.cfm
Stylocheilus striatus/Blue-Ring Sea Hare for comparison (note difference in rhinophore shape, cerata shape/placement, etc.): http://www.seaslugforum.net/showall/stylstri >
..and has shown a love of star polyp fronds (munch, munch, munch). He only loves the flower, of course.
<Oh yes, Tritoniids love open polyps!>
Wondering if we could possibly meet his coral needs.
<That could get expensive!>
He is a big fellow, about 3 inches long.
<That's unusually large for a Tritoniid, but maybe the animal's 3' all stretched out!>
At least it would be less expensive than feeding him Dendros!
<Heeee! It's undoubtedly a terrific and beautiful little Nudi, but unless you have a very large population of expendable polyps, I'd think about returning it for a credit/exchange. By the way, thanks again for sharing the photos!>
<Take care, LynnZ>


FAQs about Nudibranch Identification 7

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