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FAQs about Sea Slugs, the Opisthobranchs, Identification 1

Related Articles: Sea Slugs, Nudibranchs,

Related FAQs: Seaslug ID 2, Seaslug ID 3, Seaslug ID 4, Seaslug ID , Seaslugs 1, Seaslugs 2, & FAQs on: Seaslug Behavior, Seaslug Compatibility, Seaslug Selection, Seaslug Systems, Seaslug Feeding, Seaslug Disease, Seaslug Reproduction, & Marine Snails 1Marine Snails 2Marine Snails 3 Nudibranchs, Nudibranchs 2, Nudibranch Identification, Nudibranch Behavior, Nudibranch Compatibility, Nudibranch Selection, Nudibranch Systems, Nudibranch Feeding, Nudibranch Disease, Nudibranch Reproduction, Berghia Nudibranchs, Snail ID 1, Snail ID 2, Snail ID 3

Fuge hitchhiker ID, Green Slug'¦..   1/28/07 Greetings Bob & Crew!! <Hello.> The other evening, I wandered through my fish (laundry) room and stopped to look at the pods crawling around my 40-gal sump from my 125 reef in the next room.  I swear I saw a leaf from one of the algae move....and I realized that it was alive!!!  It looks like a land slug, but all green.  Only about an inch long.  No idea how long it has been in there or when it came in. It seems happy to crawl around the ample macro algae in the tank and just graze. I've done a few searches and can't seem to find anything like it. Any ideas what it is???  Pic attached. <Well, from the photo it does appear to be a Nudibranchia. I will say first off that by photo alone'¦even with the actual specimen in front of you, it is quite difficult to i.d. by exact species.  They are mostly very, very difficult to care for and have notoriously short life-spans in captive environments. However, occasionally, some survive'¦.as appears to be the case with yours.  It likely has a food source, and judging from the color of the animal, (as you eluded to) it appears to negotiate a large sum of vegetable matter, algae, into it's diet.  I would just observe and enjoy.> <<Mmm... likely another Opisthobranch group... RMF>> Thanks <Anytime.> -Ray <AdamJ.> PS  GO BEARS!!!!! <We don't have a football team in SoCal'¦.lol.>


Leslie's Lettuce Nudi - 10/24/05 Hi Bob and Fellow Crew Members, I seem to have a little troublemaker in my tank. This cute little guy showed up a week or so ago. I noticed my gorgeous piece of Maiden's Hair or Turtle Grass (Chlorodesmis) slowly getting smaller and smaller. I wondered where it was disappearing to since there was no evidence of it "shedding" and seemingly disintegrating like one I had a while ago did. This afternoon I noticed this little guy in the middle of what is left of my poor pathetic looking Maiden's hair and am pretty sure he is responsible for it slowly diminishing in size. Can anyone ID this little guy or know what other trouble it might cause in my seahorse corral? I have some gorgeous red macros Meristiella and Botryocladia. The Meristiella seems to be a fast grower and is growing amazingly well. I wonder if this critter likes red macro as much as he seems to like greenery? Will my reds be next? Thanks so much, Leslie  <Although mine are paler in color, it looks identical to my lettuce Nudibranch.  HTH, Jeni/PP>

<<Leslie,   This critter looks a lot like the group of slugs sold as "Lettuce Nudibranchs". Ounce for ounce, they are quite voracious herbivores, although sometimes they are quite specialized in what they eat. There is no doubt what this one likes!  These critters are totally safe to tankmates, but are often harassed and picked on. They also are quite easily injured or killed by powerheads, drains, pumps, etc. The most specialized can starve when their preferred food source is exhausted. I would suggest that you either remove it to salvage what is left of your Maiden's Hair or enjoy it as long as it survives. If you remove it, pass it along to someone else that is trying to contain a nuisance algae problem.  If it isn't all that specialized, they can help.  Adam C>>

Leslie's Lettuce Nudi - de Justin I'm about 99.999% sure that it is a lettuce Nudibranch.  The only thing that is stopping me for a second is the color. This guy eats algaes of all types and its color becomes what it eats if you will as it uses the plant chloroplasts and puts them in its skin and uses them to make food for it as well. Very interesting character and other than being very algae unsafe its a great animal. If you are a macro algae loving person then remove it ASAP. Otherwise let it do its maintenance chores and save you some scrubbing.  If you don't want it ill be glad to take it, I love the little tykes.  Justin - Jager

Marine... slug Here are 2 pictures of something I saw moving around in my tank and I have no idea what it could be? Maybe you have seen one before or no what it is. It is about a quarter of an inch long and moves around the tank like a slug. The color is a brownish green and looks like it has antennas on the front of the head.                                    Thanks Shawn <I see it... good pix. Some sort of Nudibranch I think... please see here: The Sea Slug Forum (great online scientific resource) http://www.wetwebmedia.com/nudispt3.htm or this link at the end of this area. Bob Fenner>

Greek Goddess I went to my local fish store and seen a Greek goddess it was deep blue and purple. I have never seen colors so bright before. Is this creature a slug, snail or what? <yes on all counts... AKA shell-less snail, sea slug> also is it reef safe? thank you frank. <tough to say...no one can keep them alive. If your LFS ordered this animal (as opposed to having received it on substitution/without ordering it) the I have little respect or regard for their irresponsible business practice. Please admire this animal from photos for now. Anthony>

- Mystery Slug - Hi, <Good morning, JasonC here...> I have a 30 gallon tank that has been cycling for 5 weeks now. I have a lot of algae so my first live stock purchase has been 4 turbo snails. While at the aquarium store the sales person told me that the black slug they have will also help clean my tank. So I purchased it. Once in my tank I noticed it seems to be more of a nocturnal creature and it is very active moving all over the tank. However I don't notice it cleaning anything. I am wondering what it really is and what I should feed it? I will try to describe it....... It is a very interesting creature. it is a black velvet color with what looks like veins running through it's body. The veins are iridescent, greens, blues and purples pending on the light or its mood I guess. It has two antennas with white tips and what I can best describe as a short elephant like trunk on top of its head? On the mid/top portion of it's body are the same elephant like trunks with two in back, two in front and one in the center of the back. The trunk on the top of its head has a small opening that opens and closes.  It seems to be more nocturnal in nature. <Sounds to me like some type of Nudibranch which is a slug... being any more specific than that is a challenge as this family is incredibly diverse. For an eyeful of possibilities, look here: http://www.seaslugforum.net/species.htm And then for some further reading on Nudibranchs, look here: http://www.wetwebmedia.com/nudibran.htm > My question is, is this creature/slug really good for helping to keep my tank clean and is there some food supplement I should be feeding it and what kind of slug is it, will it bother my anemones, corals and other inverts when I start to stock these sort of things? <Well... again, it's hard to say specifically. Most of the Nudibranchs are very specialized feeders and will starve to death if they don't find the right food-stuffs. In this case, it does sound like the animal you have is ill-suited for the purpose it was sold to you for, which is unfortunate but not uncommon. As to determining the proper food... well, you'll need to do some more research in order to determine which slug this actually is, and then you'll know more about what it eats. Bad news is that in the interim, it could indeed be a danger to your corals and or anemones because there are some that specialize in eating these things. Again, I don't know for certain which Nudibranch you have and would suggest spending some time on http://www.seaslugforum.net - that is really one of the best online resources out there for Nudibranchs.> Thanks, Carmen <Cheers, J -- >

Sea Slug ID - coral eater 8/1/03 Hello, <cheers> I found this creature in my tank; I think it has been eating my leather coral. Can you identify it? I have attached two pictures. Thank you!!! Would <any sea slug with "tassels" [cerata] on its back is a give-away carnivore. The cerata are structures which hold the noxious or stinging elements of its prey. Yours is a familiar coral eater... commonly ascribed to the genus Tritoniopsis (true or not). Bottom line... it is to be removed unless your reef is large enough to grow enough soft coral to sustain it. A beautiful creature indeed. Anthony>

Sea slug/Opisthobranch resources 8/2/03 Can you provide a little more info about it? Where can I find additional information about it? Thank you. <the shell-less snails that we call "sea slugs" are well studied for their magnificent beauty and fascinating physiology. The sheer number of resources on the Internet alone is simply staggering. In our new book of Reef Invertebrates (Fenner/Calfo)[insert shameless plug here: https://secure.wetwebfotos.com/order_form.jsp & http://wetwebfotos.com/store/nma-ri.html ]we give extensive coverage to the group and list tens of resources in the bibliog.. One of the very best to begin with is: http://www.seaslugforum.net/ there are also resources/studies listing the exact diets of many Opisthobranchs if you pursue other species. Best regards! Anthony>

Snail?  Nudibranch? >Hi, WWM Guys and Girl, I think that it is a Nudibranch.  Someone at the LFS suggested possibly a limpet, but I don't think so. Don't those all have shells? >>Girl Marina again.  ;)  To the best of my knowledge this is correct.   >I'm going to try to send the pics again in a zip file, perhaps they'll come through that way.   >>Do check the extension of the file type, this may have been the initial problem, though I'm hardly an expert.   >I'm inclined to think that it is not predatory by the lack of cerata on it's back, is this a "fairly" safe assumption??   >>This I cannot confirm or deny.   >I appreciate all the hard work you guys do saving our critters from our lack of experience. >>Heh, we try.  Do hope we've been of help to you and everyone else who reads this stuff.  Marina

Sea Slug - Good or Bad? 9/20/03 Hello everyone! <howdy, Thanassis!> I saw today a sea slug o my LR and I tried to locate it in your book "Reef Invertebrates" but I could not find something similar. It is white and a little grey on the top. Its two antennas are white and on the top they are yellow. I am attaching a photo. It is really interesting to watch, I just do not know if it is safe for my reef. Thanks, Thanassis <alas, my friend... the picture is not clear enough and the subject does not fill the frame (it is so tiny in the picture). Please try to capture the animal and photograph is up close and clearly in a cup. Also look to see if it is truly  shell-less snail or if there is some kind of internal or external shell. Best regards, Anthony>

Lettuce Sea Slug Hey Gang, Happy Holidays! Anthony, (or whoever's in charge of desktop pic on daily questions page), I took these pictures earlier today. I thought they might look good on the WWM site for the daily pic! Thanks from Denver! Stormbringer. <What a coincidence... I was just scanning an Elysia (Tridachia) crispata yesterday... Your digital pix are better than my analog. Thanks for sending them along. Bob Fenner>

Sea Slug ID (12/23/2003) Howdy wet ones! <Greetings. Steve Allen here.> Question for you.  I found this sucker crawling around the tank last night.  I assumed he is a sea slug and not a flat worm.  He was a few millimeters thick, about 1.5" long and had what looked like eyestalks on one end, like a snail.  Don't know if there were eyes on it or not though.  I can't imagine it can be a snail could it, without a shell?  He looks like a Stomatellid snail without the shell.  I have many of those in my tank.  Wait a minute, I am reading in my "Reef Invertebrates" book right now that they can have a shell completely hidden within the mantle, hmm... But can they get this long?  He moved kind of quickly which is characteristic of the bunch.  Anyways, the picture is not real good, hard to get the camera to work with the flash in the dark.  Any ideas if it is sea slug vs. flat worm vs. hidden shell Stomatellid? <Looks more like a sea slug to me. You might want to check out this site and send the picture to them: http://www.seaslugforum.net/welcome.htm Thank you as always and Happy Holidays! <Same to you!> Paul

Carnivorous Slug 1/30/04 Hello,  I hope your doing great. <Hi Steve!  Adam here.  I'm great!  Hope you are too.> Last night I happened to take a look at my reef tank through a video camera with a night scope.  I noticed that something large, as big as my thumb, was on my button coral. I turned on the lights, and it was a yellow Nudibranch.  I think.  Can you tell me by the picture if this is a coral eating slug and what kind it is?  It looks as though it did damage to the button.  I just lost a bubble coral recently, and I never lose my corals. <You had it right in your subject.  The critter is more likely a slug than Nudibranch.  Nudibranchs almost always have cetae ("Frills").  Although most Nudibranchs are destructive predators, the same is rarely the case for slugs.  I would want to be certain that this beautiful critters is predatory before removing it, but I am fairly bold that way.  If you are fairly certain that it is causing damage, you should be able to catch it in the act at night and remove it.> Thanks for your help!  Steven O. Garcia <Good luck!  Adam>

Introduced predatory sea slug II 7/31/04 Hello and thanks for the prompt response! <very welcome my friend> Now that I have to "put the tooth paste back into the tube" what can I add that will eat these little buggers?   <Heehee... none in time, since any new animal you would add would need to be put through QT for minimum of 4 weeks (ahem <G>). Else you just might add an Ich infection to the fishes while battling the slug problem of the inverts. Its questionable too what will eat these noxious slugs and still be reef safe. We are not even sure of the slug species or what it eats at this point. The best recourse for now is still manual extraction> What corals do they prefer (LPS< SPS< Softies< Zoos?).   <literally thousands of possibilities here. I cannot ID the creature from the low res images as it is. You may care to browse the seaslugforum.com with hope for seeing a familiar face and gleaning more info from that> Is there any type of dip that can be preformed?   <not needed for the adults and not recommended on the corals till you know which if any they are eating (they may eat sponge ro tunicates instead)/ No need to knee-jerk react here by adding a new fish or stressing your corals with dips till you have more information> We have a large collection of rare zoos, should I remove them to another tank?  Got to love the ocean!  Thanks again for your time & help!   ~CK~ <no worries... and again, please do not knee-jerk react here. Pulling corals that may not be the target of an obligate feeding slug will only make matters worse. Manually extract, QT all new, and observe pending further ID. Anthony>

Nudibranch ID? 8/2/04 Here is a better pic of the little pests. Is there any other info you can give? Any help is appreciated, thanks <again... Ids from pictures are unreliable if even possible. I see that you used/borrowed a pic from John Susbilla.  I know this chap... he's a Bay Area club member (SeaBAY perhaps). Do e-mail John for an ID of this/his snails.  He's a great guy. Anthony>   

Introduced predatory sea slug 8/1/04 Anthony, Thank You for the fast and helpful response. <always welcome my friend> The good news is that the tank it is in is a "holding" tank, and only has three pieces of coral. <excellent news indeed! So few people take the time to properly quarantine new livestock before adding them to the display> The sand is from a container on the bottom for an orange spot goby. Since the sand is no longer needed, it will be removed. <yes... very good. Excluding those need-to-have cases like your goby, or a burrowing wrasse, sand/substrate in QT is far too risky (harboring parasites, pests, etc.). > Once again I thank you for the advice. <be chatting, Anthony>

Carol at Ocean Rider, Hawaiian Sea Hares, pix of same Hey Bob, <Carol!> So last time you called I got your message the  day after the party. What is with that? Did we misbehave at the last gig???? <Heeee! Not enough!> Call my on me cell next time at 937 XXXX. <Will do> Hey I am working on a new web site with an invert section.  Do we have Aplysia juliana or californicus here in Hawaii? <Juliana is, and a few others... See Hoover's "Sea Creatures" pp. 149-153...> I thought it was  Juliana but then someone said they don't ink which ours definitely do! I need a nice photo of one too if you have one. <I just looked... don't have a decent pic of any of the Hawaiian species!> Aloha and Cya soon?? <Yes! Coming over next month for a few weeks. Will definitely call... maybe we can all go out diving... to find, take pix of Anaspideans! Hello to your husband and the boys. Bob Fenner> Carol

Nudibranch photos  - 03/05/06 I wonder if this Nudibranch is similar to the one Arthur found on his pipe organ coral (email answered by Anthony on nudifaqs.htm page).  Found this swimming around in our quarantine system when we were finished unloading a shipment from Indo.  Enjoy. <Don't know, but it's a beauty! Bob Fenner>

Strange Seaslug 3/22/04 Hi gang! <cheers> Last night, after the lights had gone out, I was looking in my seahorse tank when I spotted what I thought was a big piece of fluff on the glass, near the top. On investigating with a torch it turned out that the fluff was, in fact, a slug!  It's about 2 inches long from the top of the antennae to the end of its tail. It's creamy white in colour and looks like a fluffy lettuce! The closest photo I can find on your site is of the lettuce slug, only my one appears fluffier.   I've tried the Sea Slug forum but I cannot see anything that looks like him. (I did identify another, much smaller, slug that I also have in this tank - perils of buying macroalgae I suppose - this one is Elysia pilusa and is also a cute little chap!) I am assuming that it is an algae eating slug and that it is not harmful to my seahorses - it certainly is beautiful and I'd like to keep it but the really bizarre thing is where it came from and why haven't I seen it before? <without a picture I cannot say alas if its safe or what it even is, my friend> I have had this particular tank for 12 weeks now (I've had seahorses for about 6 weeks). I did notice a very small, not so fluffy white slug when we first started putting macro algae in - could it be the same slug has grown into this monster in only a matter of weeks?   <yes... very likely. They are so short lived that the reproduce young and grow/die fast. Berghia sea slugs for example go from egg to egg-laying adult in as little as 7 weeks!!!> Is he likely to get any bigger?  I am assuming that I don't need to supplement his diet if he's got this big so quickly, he's obviously found something he likes! Any information you could supply would be gratefully received! Thanks very much! Lesley <We should ID it soon/first to see what it is and what it eats. Do consider buying/browsing Debelius' Sea Slug book. TMC (The MarineCenter) in UK deals this title. Best regards, Anthony>

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