Question about an Isopod in my Tank.
Hi, I have recently cycled my tank and I am noticed tons of these little guys running around my tank.  They seem to hang around the back wall and on the glass.  
<Thus far>
I recently moved and I have all my fish in a 100 g Rubbermaid stock tank for the last 3 months during the setup and cycling of my new tank.  I put 300lbs
of Fiji rock into the tank to start a new system.
I am ready to start adding my fish, but I am extremely worried that I might have the BAD isopods and I do not want to expose my fish to them.
<Me too>
I have some pictures of the creatures as well as a thread I started on reefcentral.com trying to get some information about them.  I got some responses but
nothing definite.  If you could please take a look at the thread, here you can download the images and possible, hopefully let me know if I am ok or not.  
I really want to put my fish into the new system but I don't want to hurt them.  
<Will look>
I know you guys are extremely busy, but if you could take a quick peek and maybe get back to me today that would be extremely awesome!  I met Bob Fenner at a talk he did here in Colorado at Marine Showcase.  I think he would remember me, my company is designing and building the website for Aqua-Medic USA.
<Ah yes, I recall>
Here is the link to that thread:
<A href="http://reefcentral.com/forums/showthread.php?threadid=196239">http://reefcentral.com/forums/showthread.php?threadid=196239 >
Thank you,
John Michael
<I would try a "test fish" here... perhaps a damsel or two... to see if this species of isopod is a "fish eater" or no. Bob Fenner>

Re: Question about an Isopod in my Tank.
Did you find anything out yet? :)
John
<No definitive way (from a pic) to tell the habits of this isopod species... hence the suggestion to try "test fish" at this juncture. Bob Fenner>

Re: Question about an Isopod in my Tank.
Hi, Is it true that only one kind of isopod can roll up like a ball, like a rolly polly bug?
I found this in an article and the kind that can are scavengers.  Mine roll up into a ball.
John
<Do think many can roll up... a defensive mechanism. Bob Fenner>

Sweetlips Isopod
I saw your article "Grunts, Porkfish & Sweetlips" online and your photograph of a Diagramma pictum with a couple of parasitic isopods on its head.  Did you collect any of these isopods?
<No, just took the picture>
  Would you like to have them identified?
  When was the photograph taken?
<In Pulau Redang, Malaysia, about two years ago>
Thank you.
Bert
Ernest H. Williams, PhD, Prof., Dept. Marine Sciences, Univ. Puerto Rico
<Thank you for your interest, offer. Bob Fenner>

Critter IDs Please, with photos attached The first photo is of a worm that looks like a bristleworm, but has some differences.   <agreed... is Polychaetous, but not specifically a "bristleworm".> Have seen this 3" worm on the glass of my 42 gal reef a few times during the day. Doesn't look like a bristleworm because of the "mop" head, and BWs don't usually come out in broad daylight. Photo taken at 4:30 pm, just around feeding time.  There appears to be no damage to corals or fish in the reef this worm is in. <I frankly have no idea what this worm is but am comfortable that most are overwhelmingly safe if not useful as scavengers. You might send that pic to Dr Ron Shimek over on ReefCentral.com (he has his own forum)> The last three photos are of three bugs we sucked out of a well established 72g reef in which had recently lost all our new fish, mostly dwarf and larger angels.   <my friend... please (!) do be careful. Watch your own hands in this tank. They are parasitic isopods and actually can nip/bite you. We have some data on our wetwebmedia site about them as well as in our Reef Invertebrates book. Much abroad on the net too about them. Treatment is possible but an effort> Ammonia, nitrite and nitrate in the tank at the time of the last fish death were 0 ppm.  Had the flashlights out the other night and these bugs were swimming about near the front glass, though some were walking on the sandbed at times. Looks like some kind of isopod, but I cannot say for sure from all the research I've done if they are parasitic or not.   <they appear to be to me> The bugs were about 1/8th of an inch in length when first caught. Have since set up a 5g tank with LR, sandbed and macroalgae from reefs that do not contain these bugs and have added a green Chromis to determine if the bugs will infest the fish.  Over the week the fish has been in the 5g, the bugs have grown twice their original size, have been seen on the glass and sandbed, and the Chromis remains healthy.   <the Chromis for now may be too small and/or fast> Currently in the 72 gal, at night, there are pinhead sized bugs on the glass that look like the young of the three bugs now in the 5g. Can you please ID the worm?   <I'll call him Joey> Also, can you tell from the photos of the bugs if they are parasitic? <seems so yes> If they are, I imagine a long period of time, say 2-4 months, without fish would eliminate these bugs if they are parasitic and have no hosts. <actually... they are on record going over 6 months and still surviving> It has been 3 weeks since the last fish died.  During the fallow period I am continuing to feed the tank daily to maintain high levels of nitrifying and denitrifying bacteria until the time we will stock the 72g with fish again. TIA for your time and consideration. Beverly <wishing you the best of luck my friend. Anthony>

Satan... is an Isopod?    7/17/07
Bob, I swear, if I believed there was a Satan, I imagine this is what s/he would look like:
http://www.quartzcity.net/wp-content/uploads/2006/10/giant-isopod.jpg
;-)
Sara
<Heeee! Can you imagine being on the deep sea floor bottom with a whole bunch of these ginormous rolly pollies!? No thanks! B>

Re: oh, and good luck, Isopod ID    5/24/07
Good luck finding someone to ID isopods!!! I did a summer of that as fresh marine biology graduate for an environmental survey company.  
And isopods were possibly the worst things to ID. I'm impressed if a layman can get them down to family level by eye; even with a microscope doing much better than genus was often impossible.
Cheers, Neale
<Ah, yes... I sorted and Id'd benthic marine invert.s (mainly errantiate polychaetes) locally for a couple of years as a grad student... Some eye strain now! BobF>

-Possible Isopod issues-   1/20/06
Hello all!
<Hello, Justin with you this evening.>
First of all, THANK YOU so very much for your amazing site!  It is such a wealth of fantastic information,
and is truly (in my humble opinion) the best wet-pet resource on the web!
<Well its all due to many people who help, and the crew here. Ill pass your thanks on to Bob.>
I currently maintain a 120G fish-only tank.  In addition to the 3" puffer (Diodon holocanthus), there
is also a 4" angel (Pomacanthus imperator), 4" lion (Pterois volitans) and a couple of small (1-1.5")
damsels.  Salinity - 1.021, Temp - 80*F, Ammonia - 0, Nitrites - 0; Nitrates - 5ppm.
<An interesting mix, have you seen any aggression out of the Lionfish?  most of the time puffers, and lions may squabble, much to the lions detriment when the puffer breaks off spins or nips fins.  do keep an eye out for long term issues.  You also will probably need a bit bigger tank long term for these guys as all the fish get to 15" + other than the damsels.>
A couple of days ago, I noticed a small white spot medial to my puffer's left eye.  The spot does not
look like Oodinium or ick, but is rather large (2-3mm) and flat.  This morning, I noticed two more ventral
spots... also 2-3mm each, flat, and completely circular!  They do not look like any sort of parasite
that I know of, and it seems very strange to acquire trauma with those manifestations.  Also, the spots are
bright solid white, and almost appear "indented" into the skin.  What on earth could this be? <The indented part seems very odd, as most parasites are bulges outward or bumps. It may be an isopod of some sort that has decided to attach on. they can be fairly easily treated in hypo salinity dips or by using a anti parasite medicine in a hospital tank for a few days.  However, From what you are saying it is hard to give you a definite answer on it.  Can you maybe send in a good photo of the area in question.  It would be much more helpful in identifying the culprit if one exists.  Also herding the puffer into a container and gently rubbing the area to see if it comes off or is an actual indentation may save you further headache here.  My puffer enjoys digging up substrate (I have sand) and little pieces get stuck in the spines and look very odd and are a similar size to what you are saying.  Also mine enjoys playing in the sump return pipe and getting micro bubbles all over him as well.  It could be a benign item like that.>
His attitude is perky as always, and he is eating great!  I am at a loss on this one... any ideas?
<You have me a bit stumped as well on this, but Id check the basics first, and a gentle rubbing of your finger on the area may reveal a simple answer to your concern.  Try watching it for now and see if any more appear or if they disappear all together. I will forward this to Bob for some further ideas.  If you can grab a photograph of the area and send it in as I said above, it may be much more telling.>
Thanks in advance for everything!
Christine
<Thank you for being clear, and including everything tank wise I needed to know to focus on the issue.  Hope we can figure this out.>
<Justin (Jager)>  

SW hitchhiker thing
Hello gang,
<Bryan>
Hope all is well. I have a small 20g tank with a 2-1/2" Taenianotus Leaf Scorpion. Tank parameters are temp: 76-77F, NH3:0, NO2:0, NO3:20, Sal:30. Co-habitants include many Columbellid snails, 2 or 3 Clibanarius hermits, 1-1/2" Mithraculus type crab, Zoanthid polyps, a bundle of Chaetomorpha, and the usual micro/macro tag-a-longs. Filtration is by AquaC Remora and 25% IO water change weekly. The fish did a 4 week QT, no copper, no hypo or F/W
dip. The rest of the tank (including live rock) was directly introduced.
I noted this character on the surface film, 1/8" in diameter resembling a small freshwater Argulus louse. It breaks the surface tension and begins floating downward. I can see a swimming or oscillating motion but the sucker descends in a straight path... until it contacts the Leaf Scorpion and gloms onto the fish's side. The Scorpion reacts by doing its side-to-side thing. By morning, the little arthropod-y thing is gone.
So... Is this little creature familiar to anyone? I realize the description is vague and pictures non-existent but was hoping that it is a common, non-pathogenic fellow. I will also check with Shimek.
Thanks
Bryan
<Is it grey/ish in color... Please see here: http://www.wetwebmedia.com/isopoda.htm.  Bob Fenner>   

Unidentified Creatures, Friend Or Foe? - -05/07/05
Dear WWM crew,
Although I haven't heard back from you with regards to my last e-mail, I did in fact find a picture on-line of my mystery creature and I'm afraid it isn't good news.  It's described as a my isopod although google didn't give me any links when I tried that word.  I've attached the picture to this e-mail.  The website for Tampa Bay Live Rock is where I found this picture and they recommend that you remove it immediately as it will act as a fish parasite.  Do you know anything about these creatures?
<What you have is an "isopod"...I believe the "my" was used to show possession as in "hey!  That's my isopod" <G>.  These organisms are indeed parasitic, have a read here http://www.wetwebmedia.com/isopodfaqs.htm and on the associated links in blue.>
Thank you again for everything that you guys do!
Best wishes, Karen
<Regards, Eric R.>

What is It??  Anthony's "MicroCrusty" Hi, Bob... just wondering if you have a notion what this microcrusty might be? They are rather common in fishless tanks/refugia... and usually succeed Amphipods. Their size is only slightly smaller than Gammurus, for example. I sent the pic to Rob T in Hawaii, but he was not familiar.  Any ideas? Anthony C. <Don't know either... though looks vaguely familiar.  Let's post on WWM and ask. BobF>  Grazie :) And a bit of a mention... those mantis like aspects in the front are only developed on larger specimens. The smaller individuals tend to get described like "centipedes" commonly (that is to say... they are very symmetrical... elongate with bullnose ends and sparse large legs. Hard to tell heads from tails when small) Anth- <Yeah, the fancy mouthparts reminded me of the Odonata. B> Follow-up question re: What is It?? Anthony's "MicroCrusty": Munnid - 3/3/08 Crew, <Hi Russ> First, I'd like to thank you for all you do for this hobby. All of you have greatly contributed to my success as an aquarist (through this site, your books, etc.). <Ah, that's music to our ears. On behalf of Bob and the crew past and present, I thank you very much!> My "question" is more of a follow-up to one previously asked. It pertains to the post titled "What is It?? Anthony's "MicroCrusty"" (http://www.wetwebmedia.com/crustidfaqs.htm, about half-way down the page). I would like to know if anyone has made an ID on this critter. <Yes indeed, it’s a harmless, beneficial, herbivorous little isopod in the family Munnidae, commonly called a Munnid.> I have searched everywhere I know to, and this post is the only place I can even find it mentioned. I have an abundance of these critters in my tank and refugium. They seem to thrive just about anywhere; on glass, in the sandbed, on LR, and throughout my Chaeto. <Yep, thank goodness they’re good guys, huh!> They do not appear to predatory, as I have never noticed them disturbing any of my tank inhabitants (various fish, corals, sponges, crustaceans, etc.). <That's correct. Unlike their Cirolanid cousins, these pose no threat to livestock and in fact serve as tasty fish treats.> I do occasionally see them squabble amongst themselves, or with the copepods and amphipods, <Yes, it seems to be in their nature and it always makes me laugh to see it in action. Have you seen them perform their little “dance” yet? In the photo at that link (taken from underneath the Munnid) you can see two anterior appendages folded up under the body, akin to a Praying Mantis. Occasionally, two munnids will face off, extend those two surprisingly long appendages out towards each other, grasp tips, and do an odd little dance. It lasts for several seconds then they release and go their separate ways. Why they do this, I have no idea, but it is interesting and amusing to see. It’s probably the Munnid equivalent of “You’re on my property!”. By the way, here's a dorsal/top view of one that was in my tank: http://wetwebfotos.com/usermedia/high/0/2470_145.jpg .> ..but I have never witnessed anything serious come of this (death, predation, etc.). <Nope, their squabbling always seems to be brief/not very intense.> Also, my Synchiropus splendidus loves to eat these guys. <I bet he does!> He actually appears to prefer them over copepods or amphipods. This may be due to the fact that they are much larger than the copepods (easily 10-15x), and seem easier to catch than the amphipods. <Heeheeee! Or maybe they just taste better! Seriously though, I agree with your assessment. Of the three main choices (copepods, munnids, amphipods) munnids are right smack dab in the middle, size-wise. They’re perfect for little Synchiropus/Mandarin fishes.> They are able to "run" quickly, but only do so in short bursts, and they do not seem to have any swimming ability. <Nope, they are decidedly more adapted to crawling than swimming. The only time I’ve ever see one even attempt it is when I’ve accidentally dislodged it while cleaning the glass. Graceful swimmers, they are not!> My only concern is that I am not sure how nutritional they are. I am not too worried about this, because they seem to have the same feeding habits as my other pods. Also, the mandarin has always been quite plump, colorful, and active. <Yep, I wouldn’t be concerned. I imagine that nutritionally, they’re about on par with copepods and amphipods.> That pretty well sums up my observations on these guys. <Very impressive, indeed! It’s always such a pleasure to find someone who appreciates the smaller, but no less fascinating creatures we have in our tanks. :-)> I hope this has been somewhat informative, or at least interesting to read. <Very much so.> I welcome any/all comments you all may have, even if an ID is not possible. Thanks again for all you do. Russ <It was a pleasure, Russ, and thank you for sharing your observations! Take care, -Lynn>

Here tis'