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FAQs about Sea Slugs, the Opisthobranchs 1

Related Articles: Sea Slugs, Nudibranchs,

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

Who dat?

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>

Sea slug Toxin? Oh yes  02-05-06 Morning guys! <Too cheerful...!> Just found your web sight and it's now booked marked! <And the site too?> I've been searching all over the web trying to find an answer to my problem! About a month ago I purchased a beautiful sea slug. A week later I found it dead, caught in my filter. <Yikes... am trying to put away the pix from the last trip... and am on to the Opisthobranchs... and reading re just how toxic some of them are... no wonder they can be so gorgeously colored and not predated, eh?> A week later all my fish except for one damsel were dead! ( Niger Trigger, reef beauty, Butterflyfish, cardinal, yellow tang) I forgot to mention that my tank is a combo reef/fish 50 gallon. My soft coals and one Anemone were not affected nor were the cleaner shrimp, hermit crabs and turbo-snails. I immediately suspected the death of the sea slug and sure enough read that these slugs secret a defensive toxin. <Yes... but not so much a secret to the fishes they're found with... just in the confines of an aquarium...> I performed a 50% water change and replaced all my filters. I let the tank "stand" for 3 weeks then introduced one blenny to the tank. Within 36 hours it died! It's skin was sloughing off and fins looked as if they were dissolving. <Yep> My question is; should I completely start over with new live sand and live rock??? ( the rock is still very purple in color) or let the tank recycle for a longer period of time???? HELP! Great sight, Jim <Mmm, if it were me, mine I'd try adding a good quantity, quality of activated carbon in your filter flow path, let another few weeks go by and try some other "test fishes". Bob Fenner>

Elysia crispata nutrition/feeding  1/18/06 Hi my name is Beth and I just received an Elysia crispata as a  gift.  As interested as I was with this gift, I know it can spell disaster  if I do not get enough information on him as quickly as possible.   Basically I need to know if it will eat Caulerpa or not. ( I have heard  contradicting answers). <Some do, but not exclusively, enough... and can be trouble> Also I do not have strong enough lighting for  corals but my macro algae does great... maybe too great.       If this guy needs a different environment let me  know, and if the Caulerpa isn't appropriate please tell me what is ... along  with the common name so that if I need to get some even the kids at the store  will know what I am talking about.          Thank you for your time...  my lettuce slug thanks you to!                              <Mmm, more fine, filamentous greens. Please see here: http://www.seaslugforum.net/display.cfm?id=12310. Bob Fenner>                                                      -  Beth

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

Sea Slugs I saw these guys for sale at Foster and Smith. They look cool, but other than on their site, I can't seem to find much info on captive care. Are they good for the friendly neighborhood reef tank?  Any information would be much appreciated.
<Matt, here is a link that will take care of you. http://www.seaslug.info/factsheet.cfm?base=hamicymb. James (Salty Dog)> Thanks  <You're welcome> 

Waging war on hair algae Bob, <Mike G here> I wanted to get your thoughts on introducing a Sea Hare to take care of some painful green hair algae? <Sea Hares are wonderful consumers of hair algae. It may aid you in physically removing algae, but will certainly not solve your problem single-handedly. They are messy eats, and minute particles of Hair Algae WILL get released every time they take a bite. Also, their feces will contain partially digested hair algae, and possibly hair algae spores. A sea hare would be a wonderful warrior in your battle against hair algae, but you need to also eliminate the problem that is causing the algae in the first place.> I've had the aquarium up 8 years and have never had a battle like this with hair algae - I feel I'm starting to lose the battle. <That's a very common feeling when one is pitted against hair algae. I had problems with it when I first started my tank (15g). It was completely eradicated by doing 2 gallon (10%) water changes every other days and by adding a refugium of 25% of my water volume (5g) to my system.> It's been going on 8 weeks now. I've seen 2 Sea Hare species for sale: Aplysia punctata & Dolabella auricularia. Fosters & Smith rates Aplysia punctata as extremely delicate/expert with serious negative affects from possible ink secretions. Aplysia punctata isn't found on WWM. <I recently purchased a Sea Hare to control my Caulerpa problem. The only species available was Dolabella auricularia. I can assure you that he does a goodly job on Cyanobacteria, Bryopsis, bubble, and pretty much any microalgae he comes across. I think that if he were to come across hair algae, he would eat it with gusto. Of course, he does not eat Caulerpa. It figures.> Dolabella auricularia is mentioned twice on WWM and a seller of it praises its traits without a mention of any issues with the species. I know it also secretes ink as well, but what about hardiness? Would you pick one over the other & how toxic is the ink? <Mine has "inked" in my tank twice now...either time with absolutely no negative effects. Granted, I do run a skimmer that is quite large for my tank (CPR BakPak), and I did a 10% water change as soon as it inked. Upon researching hares, I have found that Aplysia produce a considerably more toxic ink than Dolabella. I think a Dolabella would be the way to go if you decide on getting a Hare. As a side note, the hare toxins can be easily removed with carbon and a water change.> For back ground, I've been following all the algae reduction husbandry: All water changes & evaporate top-off done with buffered/aerated RO water from Kent Maxxima Hi Silicate (changed out all membranes 4 months ago), 30% water changes every 2 weeks (every one now), thaw, rinse & strain food prior to feeding, careful not to overfeed, 1800+gph turn over, over-powered skimmer (AquaC EV120), 45gal refugium w/ DSB & Chaeto, 520w PC lights that were recently changed, phosphates reading zero, but running PhosGuard as precaution. The green hair algae is still kicking my tail. I think I've narrowed down the original cause to a partially blocked line on my skimmer, which started the outbreak 12wks ago and then was fueled by a continuing die off of all my turbo snails (past email). About 6 weeks ago, 20 Turbos went through QT for a month - lost about 3 in QT. At the time, I thought it was just a natural/unlucky die off. Since they've been introduced into the main tank I've lost about 18. Originally, only the new ones seemed to go. My old ones are covered in coralline algae, so they were easy to tell apart. Now the old ones are going too, seems like one every 4-5 days and that's just the ones I can see. My 30+ Cerith & 40+ blue legs seem completely unaffected. My two "indicators" - RBTA and Hippo tang couldn't be better. I brought the Turbos in to help combat algae problem - now I think they're fueling it. I'm to the point now of thinking about taking all the Turbos out & putting them into QT. Any thoughts? <Certainly. If I were you, I would remove all of the turbo snails, as they do not seem to be doing anything more than providing nutrients for an algal bloom. It sounds as if your refugium is completely adequate, so you can't really expand on that. What really ended my hair algae infestation were 10% water changes every other day. This may be extremely difficult for you considering your tank and refugium sizes. However, It may very well be worth a try. You may also want to look into a high quality phosphate reducer. Lately, more and more people have been reporting success with PhosBan. It really all depends on what you think would work best in your situation.> I've been scrubbing the LR manually with a toothbrush & then immediately doing a water change to try and remove as much of it as possible. Last week I thought I delivered the final blow by spending 4 hours and manually scrubbing every single piece of my 180lbs of LR, one at a time, always submerged, in a bucket of saltwater from the tank. I used 3 separate buckets of saltwater to keep the algae export as high as possible. I certainly staggered it, but it looks to be getting back up. With the toothbrush method, do you think I'm doing more harm than good by spreading it around? My thought was that dislodging it and removing some though the filter & water change would be more effective than just letting it grow unabated. Any other advice? <I think that you are only spreading it more when you scrub it off the rocks. You are releasing minute particles into the water, which can easily find new places to lodge and form new "colonies" of algae.> Since I've been way too involved in algae recently, I wanted pass on a personal observation that the most productive hair algae remover in my tank is my Foxface Lo (Siganus vulpinus). After watching my tank for hours, he is certainly outperforming my robust lawnmower blenny and seems to be getting the better of my spineless clean-up crew. I've seen him wipe out 3 long sprigs of hair algae in a 90 second window. I just haven't seen him get much press for that on WWM or anywhere else and besides, he's a gorgeous fish and I haven't seen a single negative trait from him (having slightly venomous spines probably doesn't help him, but I'd find it hard to see how I'd get stuck by him). Just wanted to sing the Rabbitfish praises a little. <Rabbitfishes are well-known and wonderful herbivores. Glad to hear yours is working out for you.> BTW - wanted to get your thoughts on a sump/refugium I've designed and am thinking about having built. Especially concerning transition methods from one chamber to the next. I've attached the layout. As a note, the PVC return pipes in the refugium will be covered by a 6" DSB & the 2" ball valve into the refugium is designed to support complete gph control through the refugium. The overall design goal was to maximize the efficiency within the footprint & have an uncluttered/clean appearance. All my aquarium equipment is in the mechanical room below my office, so space isn't an issue. My current sump/refugiums were born from a series of upgrade bolt-ons over the years. Restricted water flow through the refugiums, wasted water volume due to in-line plumbing spacing & general clutter were the reason for the potential new sump. <I see no problem with your design for your sump/refugium.> So sorry for the length of the note - I just realized how long it is. Obviously, I'm excited about the hobby and can't express the gratitude in having the joint knowledge of WWM available to me and other enthusiasts. Get to me when you can & feel free to break the note up if it makes for easier reading. <The length of your email is not a problem. I can only hope that I have provided answers to all of your questions. Mike G.> 

Feeding lettuce Nudibranchs <Hi Kerry, MacL here> I am wondering what types of algae the lettuce Nudibranch  eats?  
<I'm quoting here from http://www.seaslugforum.net/display.cfm?base=elyscris&id=3863. "In choice experiments they found that E. crispata would eat a number of species of siphonaceous green algae including Batophora oerstedi, Bryopsis plumosa, Halimeda spp, Penicillus spp, Caulerpa paspaloides and Caulerpa racemosa. Jensen & Clark (1983) later showed that another species of Caulerpa, C. verticillata (a very finely branched species, which looks a bit like a tiny Christmas tree), is the preferred food of the juveniles of this species."> And a second question is what kind of algae is the green film that grows on the glass of the tanks and is this one that the Nudibranch eats?
<Difficult to answer could be several different types.> Thanks for All the info on you website It is my main source of Info in the hobby. <so glad its been of help to you. Good luck, MacL>

Missing Nudibranch Hi guys, hope you're all doing well... << I am. >> Was hoping you might shed some light on a new addition gone MIA. I added 2 lettuce Nudibranchs to my tank a couple days ago as part of a two-fronted attack on hair algae (finally got an RO/DI-- Kent Maxxima-- fertilizer-free water changes to come!), but one of the fellows has gone missing during the 1st night. << Are you sure.  They may hide well. >> No signs of it stuck against a power head (all are screened off), & no sign of him in the overflow compartment either. I'm wondering if a tankmate may have eaten him. << Possible, but I'll say unlikely. >> Basically my inhabitants are currently a Mandarin Dragonet, 2 Green Chromis, a Lysmata amboinensis shrimp, a Spiny Brittle star, a Favia brain coral, some Discosoma & Rhodactis mushrooms, assorted red & blue legged hermit crabs + one scarlet reef hermit, & some Astraea & turbo snails. My 1st suspect is the brittle star-- I'm thinking that with his long searching arms it may have come across it & probably could have caught it pretty easily. I don't think this guy is actively predacious, but could be opportunistic? << Doubtful. I wouldn't think of him as the problem. >> My next suspect is the scarlet reef hermit. The only reason I really even consider him is because I had caught him eating a "Red Footed Conch" that I had (never was able to truly id this guy). << Well, that is possible as well, but hermits are more of scavengers and are more likely to eat it something that has already died. >> The hermit would pry open the conch's little 'door' & was picking out matter from inside. I removed the conch & put him in the fuge, but it didn't make it. I haven't caught the hermit assaulting any of the Astraea or Astro, but one wonders... My last suspicion is the Rhodactis mushrooms. One of them is about 4 inches across, & I have seen them close up on morsels that drift onto their surface. I wonder if the Nudibranch could have floated onto one accidentally & been consumed before he could high-tail it off? << Doubtful again. >> What do you think the likelihood of any of these scenarios seem to you? Are the lettuce Nudibranchs 'distasteful' enough that these shouldn't be a concern? << I would bet he simply just died.  They aren't that hardy and being transitioned into a new aquarium may have just been too much.  They often get blown around by powerheads into the rocks and things like that.  I wouldn't think it was predation, so much as unfortunate circumstances. >> I'm trying not to assume the worst, & bearing in mind that he could have just gotten into the rockwork somehow & not being plainly visible, but I'm also thinking that because these guys are partly photosynthetic, that they should hang out in the light, on rocks' surfaces, more or less, right? Thanks for any insight you can offer... << I'd probably not try another.  If you are having a hair algae problem I'll assume you have a water issue problem.  I don't like adding delicate items to a system with water problems. >> Pete Cushnie <<  Blundell  >>

Lettuce sea slug.... Hello,  I checked the FAQ page I was directed to, but found no info regarding this...I have a lettuce sea slug.  It a appears that it has shed its frills...it is much shorter now, grazing on rock, a nub of its former self. I saw the frills briefly, but they have not reappeared. Did it divide itself or was it chomped in two.
<< I doubt it divided in two.  It is possible, but I don't think lettuce sea slugs are known for that.  Why did you buy one?  Most people buy them to control Aiptasia, <<??? What AdamB? RMF>> and they do very well.  But after it consumes all your Aiptasia, they will often starve.  Something to keep in mind, in case your tank is Aiptasia free. >>
I have no experience with sea slugs, I've had this one about a week. Thank you, Beverly   <<  Sorry I can't be of more help, let me know how he looks in a few days.  Adam Blundell  >>

See here... Sea hare 5/3/04 Tube Anemone Good evening my wonderful reefers! lol <live it, swim it, smoke it... er, well.. two of those things at least> I won a Aplysia dactylomela the other day at a raffle.  I won it on purpose out of sympathy, I didn't want it to end up with some poor bloke w/out a clue where it would starve to death. <interesting... perhaps a polite mention to the club/donors to be more conscientious about submitting items of challenging needs for random win/purchase by others> After a bit of hunting around my tank for some red algae (which proved non-existent, the info on the specific type of algae these guys eat is rather lacking, a lot of authors say they eat red algae they just don't specify what kind! I think it must also take them a while to adjust their diet to green algae) <I do not spy it quickly at hand... but we have a link in our bibliography for our Reef Invertebrates book to a web page that lists the exact foods for many species of opisthobranchs> I tried putting in some red/purple Nori by Two Little Fishies (Julian Sprung & Co) and my guy started to chow down. Since then all it does is eat and sleep. hehe <Ahhh... good to hear> I was wondering if you could tell me approx how long this sea hare lives?  I've read from 1-2 years is all.   <hmmm... I am not certain, although I recall the larger temperate species living somewhat longer than the typical 24 months or less> Do they live longer if they don't mate?   <nope... not to my knowledge. There is precedent to support this in other mollusks (like the famous octopuses with a defined lifespan, breed or no)> It's funny, I live in Miami and went snorkeling the other day and saw a mated pair of Dactylomelas.  I didn't know mine was the same even though I've seen them many times when I snorkel. Also, treading into dangerous waters... are there any colorful Nudi's that can be easily kept in a reef tank or is this a lost cause? <hmmm... sort of. The key to any Nudibranch is identifying and supplying their food source. Many will keep and breed easily if you can do this. I keep an active colony (several hundred!) of beautiful blue Berghia (Aiptasia eaters). Other folks keep and breed Elysia sp algae eaters... some folks even dabble with the Zoanthid eating species. The problem with keeping in reef tanks is that most such systems have excessive powerheads and overflows. If you plan well though, you can keep some beauties> I always feel so bad when I see these really amazing looking, doomed Nudi's at the LFS.  There should be a campaign on to stop the collection of specialized feeders such as these. <no formal campaign is needed. Educated aquarists simply vote with their dollars and do not buy them. They die in the dealers tank, and when it happens enough times, the dealer stops ordering them <G>. You might help this along with  a polite mention of the reality (supported by a helpful list of web links or photocopied documents) that you give to the LFS. If that doesn't work... tell us their name and we'll post them on the wall of shame <G> Ha!> Oh, about how big will a tube anemone get in a reef tank?   <it won't... because it does not belong in a reef tank and will never be placed there by a conscientious aquarist. If you know of anybody tempted to the contrary, please direct them to our extensive archives at wetwebmedia.com for an explanation why not <G>> Will I need meters of sand eventually? lol I hope not. ( <8-12" would work nicely... let it mature for 6-12 months before putting a Cerianthus in a species specific tank (no corals or other anemones unless you intend to sacrifice some)> Ah, the pot calling the kettle black I know, but I'm going to try and provide for it) It's only 3 inches long at the moment and eating fine. <sigh... disappointing> Thanks for all your help! Love you guys, Morgan <sob...sob... another anemone destined to be a statistic. Anthony :p>

Sea Hare with a Mascot? I just bough a sea hare yesterday he is about 5 inches long and pale yellow with round black O's on him. <Cool> Today I saw something come out of his hole. It looks like a little pink crab about 1 cm. The crab was then crawling all over my sea hare. Should I try the remove the little pink crab? and if so how? he is very small.
<I would quarantine all new purchases so that removal is easy.  I have no idea what sort of crab this is without a picture, or if it is suitable for your system because you haven't included details.  Picture perhaps? Ryan> Thanks for your help

Sea hare?... pass 4/12/04  Hi There  <howdy>  My LFS has sea hares they are selling for which they claim is algae and Cyano control. I have heard before that the sea hares can consume Cyano.  <some do>  These dudes are real ugly rock like critters. Do they really help control red algae/Cyano??  <its likely a moot point. The few sea hares that make it into the aquarium trade are typically temperate species (cool waters). They are naturally short lived to begin with. Not a safe or recommended choice IMO. Furthermore, they would be treating the symptom (Cyano) and not the problem (nutrient control). Focus on the latter my friend... we have many recommendations for this in the archives. Do a keyword search from our home page at wetwebmedia.com for "Cyano", "sea hares", "nutrient control", etc. Anthony>

Half of a sea slug 3/28/04 Hi, How are you guys? <swanky> Thanks for the answer about filter media. I have a strange sort of a question. Nearly a month ago I discovered a small sea slug  on a piece of LR, after reading about their potential deadliness, (from your site) say if they die in your tank I have been watching him closely. <there is at least some slight reason for concern here. Do be cautious> It appears he eats hair algae and has subsequently tripled in size and begun freely roaming the tank. Yesterday I saw him suspiciously close to the input hose of my Fluval 404, by the time I next checked he had disappeared and I did not see him for the rest of the day. My paranoia drove me to check my filter and I discovered him inside. After having to pull all the media out, I rescued him only to find more then half of him was missing. He was still getting about fine so I put him back in the tank. Its the next day and he is calmly back to eating algae. I was wondering if its possible he will survive (longer then he has) and how much a problem the missing half will be. <it may survive and heal/regenerate... although these are natural short-lived organisms to begin with (months)> I have looked everywhere for his missing half and while he is only about an inch and a half (original length) I'm a bit worried what impact it might have, even though it may be in the filter. I was also wondering, I bought a brown bubble tip anemone three days ago and it has been hiding (tentacle and bubble tips looking fat and normal) under a poorly lit cave, is it just acclimatizing or should I be worried (if it matters I have only two 40w fluor lights, one blue, in a 60g tank). <really no worries... such small matter. Simply do a large water change or two in the next week for safety> I have had a small phosphate jump up to 0.25 (which I am bringing down) but all other tests are fine. Is it also true that tanks go through different stages of algae growth while they are maturing? <yes... it is called algal succession. It is natural an inevitable. We describe it at some great length in our plants and algae chapter in our book "Reef Invertebrates"> Sorry about the length of the question and thanks a lot for your assistance - Mr. Blue <kindly, Anthony Calfo>

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>

Spitting Sea Slugs 1/21/04 Hello Chaps and thanks for a wonderful website. <Hello from the left side of the pond!  Glad you enjoy WWM.> I have a 40 gallon tank with loads of Fiji live rock, two true tank bred clowns, two green Chromis and a tank bred flame angel. The tank has been running for a few months with no problems, thanks to lots of reading of your site. I have a slight concern over what seems to be a group of sea slugs in my tank. They generally appear after the lights go out . I have seen about three of them together so I assume there must be more. I noticed the other night that they occasionally spit some sort of brown fluid. They are about  1.5 cm long and dark brown. Do you have any idea what these sitting creatures are and should I remove them? They don't seem to spit at anything in particular but your advise would be greatly valued. <A picture is worth a thousand words or more.  ID is difficult without one.  If they are surviving in your tank, they are getting food.  Many are herbivorous, some are carnivorous.  I don't know what the "spitting" is, but it is probably just excrement, but could be spawning material.  There are some internet sited dedicated to sea slugs and Nudibranchs.  Perhaps you can find a match there.  Best Regards!  Adam> Thanks again.  David

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

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 - 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>

Sea slug - good or bad? ... the cerata never lie: bad 9/29/03 Hello Anthony! <cheers, Thanassis> I received your book :Reef Invertebrates. It is excellent! Congratulations to you and Bob for the good work! <thanks kindly my friend> Here are a couple of photos of my sea slugs (they are about 10 now) . I hope they are better than the last one I sent you. Thanassis <alas, I must tell you that your sea slug is a carnivorous species... likely to prey on some kind of corals/Cnidarian as evidenced by the cerata on the back (used for storing consumed stinging cells from their prey). If you have any Alcyoniid leathers (finger or mushroom leathers especially) in the tank... I suspect they are viable prey for these slugs. My advice is to remove them. kind regards, Anthony> 

Carnivorous sea slugs 10/18/03 Dear Anthony, I removed about 15 slugs as soon as you advised me so, but after a week I realized that they are really many of them in my tank, the tank is full of baby slugs. Any advice how to remove them ? <I'm confident that diligent manual removal for the next week or two will eradicate them. Natural predators are fewer in number and without a specific ID of the slug, I could not recommend one at any rate. No worries though, I still feel that manual extraction (by siphon... never by hand as some are poisonous) is the best solution. Best of luck (and always remember to quarantine new rock/sand/fish/coral after this <G>!). Anthony>

Tank Update and Nudibranch Question (refugium and algae control FAQs) Hey Bob, Just wanted to give you an update on my tank. My nitrates are down to 30 after 3 weeks of weekly 25% water changes. Am still battling some hair algae but everything seems to be doing well.  <Ah, good> Since I have some left over money I have decided to buy a CPR hang on refugium. I want to put some of my remaining tang heaven and get some more algae to help me export more nitrates. Have you ever used one of these units or have you herd anything about them?  <Yes, we have some of Suk, Tom and the boys from Arcata (CPR) refugium units on test tanks... with about the same CF lighting we all use... We've been building, using very similar gear (ours have skimmers, calcium feeders on them in addn.) for years... these do work> Also, I have been seeing algae eating Nudibranchs advertised on several web sites. (some call them sea hares) The also say that they are easy to keep. Is this just a marketing ploy or do these really eat hair algae and easy to keep?  <IMO/E more of the ploy... don't like the use of Aplysiids (Seahares) for this application... can/do cause some real troubles with water pollution at times... Would look to other algae eaters> I certainly wouldn't want to buy one to have it starve and die in my tank possibly killing all of its inhabitants. Thank You, Jonathan Pac <Good point... Do read, re-read the most recent updates on "Marine Algae", "Algal Filtration", "Algae Control" on our site: www.WetWebMedia.com here. Bob Fenner>

C. varians Hi Bob, I have had a problem with the ubiquitous Planaria a.k.a. flatworms, and have purchased two C. varians to try to combat the problem. I have turned off my power heads until I can get foam filters on them, but am wondering if there could be any critter in my tank that might like a C. varians for lunch. Can you tell me what might "go after" my little flatworm eaters? <Any number of worms of different phyla, crustaceans of size if they're hungry. Where did you get this Chelidonura? Bob Fenner> Thanks, Marty

Re: C. varians Hi again Bob, Well I do have some small crabs that I bought from GARF. I don't recall what type they are so I have attached a pic. Other than some snails, that's it for sessile inverts <Umm, actually these aren't "sessile"... that is, they live on the bottom, but aren't "attached" to it permanently... so they should be able to keep out of the way> other than what's living in my sand bed. As to where I got them, your friends at FFExpress. They were quite pricey, but if they do the job I'll be happy. <We'll see... Bob Fenner> Thanks, Marty

Green Slug Hi Bob, thanks for your info on the Fingerfish. I got a Green Sea Slug (Elysia) last week. It is doing fine. Yesterday, it started to lay eggs in a spiral pattern. Are those eggs?  <Yes> Will they hatch?  <Perhaps.> Will they live?  <What will they eat? What is the species life cycle, developmental history? Insert the name in your search engines and find out. Bob Fenner> Thanks.

How about a sea slug? The local store has a sea slug they got in yesterday. It is 7 inches long, fleshy, 2 inch tentacles(?), and bright pink w/ light green areas. I couldn't find any hard information on what kind this is and if it is a trouble maker. Any idea? Trisha <This is a big sea slug! Don't know which species... perhaps an Aplysia... please see this tectibranch coverage: http://www.seaslugforum.net/aplyextr.htm I would not buy, try to keep this animal... too much likelihood of trouble... it being cold water, having a narrow diet/food preference... too great a likelihood of it dying, polluting your tank. Bob Fenner>

Re: Giant, Mystery Sea Slug Thank you for the advice. Man it is really a beauty. Hard to resist but not worth the trouble. Trisha <We share the same opinions. Bob Fenner>

Greek Goddess... Chromodorid, Nudi 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>

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

- 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 Slugs; get rid or not to get rid?! Hi Guys, thanks for your previous help, been of great use!. Just a quick question , after reading up on the Opisthobranchs and the like I still have not come to a decision on whether I should get rid or keep! Background: Last week one very small 3-4mm white and yellow shell less slug found sliming across the front glass, a couple of days later 3 white and yellow shimmy's , a couple of days later 6 shimy's, and what look like coiled laid eggs! Could there be a pattern emerging?! Should I try and remove them or let them get eaten. Many Thanks for your help <lets ID the slugs family/group first to get an indication of what it might eat. Please notice the distinguishing features/structures listed here on WWM between groups... check http://www.seaslugforum.net for comprehensive IDs. Also... look to see if your slug has "tassels" on its back... (cerata)... if so... your slug is a predator on cnidarians like coral. Best regards, Anthony>

Reef Safe Nudibranch - 3/28/03 I am very sorry I tried to look this up but either I am looking in the wrong places or I am blind. <No problem> I just want to know if they are reef safe. <Elysia (sometimes referred as Tridachia) crispata are known to be reef safe. Check on the forums at the many reef sites and more importantly check out http://www.seaslugforum.net and http://www.wetwebmedia.com/grnalgcont2.htm Please take the time to learn about the environmental conditions and the specific needs of this useful but delicate animal> My LFS has a real nice looking one and I want it but don't want to loose coral. Any help is appreciated. <No worries. Paul> Shane

A picture paints a thousand words (hitchhiking slug thing) - 3/26/03 Hi, <Hi Paul here today> Firstly, thank you for providing such a valuable resource for the rest of us. I have an intriguing looking sea slug (or similar) that I would like to put in my main tank but I'm jostling with a little paranoia. <absolutely understandable.> It's history goes like this: I received a shipment of a few pieces of live rock and one of the pieces had punctured its bag, so there was just a little water left around the bottom, when I opened it the smell nearly knocked me over. <Yeah, know the smell well.> At my Wife's directive I put the stinking rock in a tank outside the house and following the directions from Bob's book managed to "re-cure" the rock. <Very good> As the live rock cured a very tiny slug-like creature could be seen in the tank. It is now about 5-6cm long and has been growing like "the blob" It looks just like a garden slug except: it is a mottled light brown colour has small spikes all over it, two feelers, two horns, and a hump on it's back, with  a hole that it can open and close from where it breathes and defecates. <hmmmmm maybe a limpet.> It's host live rock is now in my main tank and the slug is still in the quarantine tank where it continues to graze on  algae on the sides of the tank as it has always done. <Are you sure it is grazing? Just curious, not discounting your claims> My question is simple: Can I safely put this cool looking creature in my tank? <Not enough information for me to give you sound advice. I would primarily be concerned with positively identifying the animal first and foremost.> I have scoured every source of information, I can find Including Bob Fenner's great book ( which incidentally cost me $160 Australian or about half my take home weekly income!)<Whoa. I am sure he thanks you very much!> which has me freaking out about the horrors, Nudibranchs, Sea Cumbers, etc can cause in a tank. <Very true but they are just fulfilling their purpose in normal stable reef environment. In a closed environment a different result unfolds.> My worry is that I haven't been able to find out if my new friend could do the same or would serve as a loyal cleaner? <Hard to say. Can you send a picture? We really need to identify before any advice for placement could be ascertained> If it is any help the L.R originated in Western Australia, had heaps of Caulerpa Racemosa on it and other macro algae, and during its 're-curing' had countless water changes with natural sea water (yes, I have read that synthetic is preferable- but where I live, 7 hours north of Sydney, the water is pristine and free)<If you get it far from the coast, in my experience. Nearshore/Inshore waters sometimes (read most times) collect inland pollutants. Keep an eye on your water and livestock if used as sometimes your lucky and other times well.....unlucky> I would really appreciate it if you could help dispel my fears. <Please send a picture if you can. Go from there. Even if the picture is someone else's from another site. Identify, identify, identify is the key here! Sorry for the delay, but hopefully you have been able to hold off on placement until you know more. Thanks for the question, Jeremy.> Jeremy.

Opisthobranch Nudibranch (sea slug) Eggs - 2/17/03 My Lettuce slug left this on the glass.. Do they look like eggs? <They are indeed conspicuous sea slug eggs. A delightful event to see. Kudos, Anthony>

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>

Ugg, Slug problems on corals Good Afternoon Mr. Fenner, <Anthony Calfo in your service> Having tried to find some info on the WWW with not too much luck, I was wondering if you could advise me on what to do with a slug problem, I am having in my tank. I live in the UK, and am quite new to marine fish, having kept tropicals for years. My tank is 60 UK gallons, I have live rock, live sand and coral sand as a substrate, >> Livestock >> 1 fox fish >> 5 green Chromis >> 2 percula clowns and bubble tip anemone >> 1 orange spot goby >> 1 small blenny >> 1 dwarf cherub angel and an assortment of soft corals, also have 2 cleaner shrimps, 1 blood shrimp. And a clean up crew of critters i.e.: blue and red hermit crabs, and turbo snails. All of which are doing very well. I am running an Deltec APF600 Protein skimmer,1 UV Sterilizer. I also have 2 large Eheims,  plus an internal filter for the filtration, and 2 power heads for the moving of substrate. And my problem is I have star polyps which are currently infested with these slugs ! they are small and white, and have completely decimated 1 coral, and I am now afraid they will start on the other one. So do you have any advice on how to dispose of them, without using chemicals in the tank, as I am against using anything in the tank, is there a fish or something I could put in that will happily munch on them. <yes... you can use a wrasses species like the six-line wrasse. There are in fact many other species that will work well. The best bet if to move this coral(s) to the quarantine tank while you QT the new fish for 2-4 weeks in isolation. This will force the new fish to eat more and do so faster while the stranded slugs in the display starve without a host> I also use an R/O Unit to make my own water, and I am about to change my salt to tropic Marin, after using Kent sea salt, as I was advised this was a better quality. <A VERY wise move in my opinion> Hope this isn't too long winded ! but I felt if I were to ask an expert, such as yourself you would need to know all the statistics. <you've done an excellent job of providing background information my friend> The tank has been up and running for 7 months now and no losses. Hope to hear soon. Yours Sincerely, Sue Coveney <Sue, to avoid these problems in the future... please be sure to QT all new corals, live rock, etc for 2-4 weeks just like fishes. Else you take a great chance with every piece of livestock added fresh to the display. Best regards, Anthony>

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