Please visit our Sponsors
FAQs on Methylene Blue, Use in Ornamental Aquatics

Related Articles: Treating Marine Disease, Methylene Blue, Dips/Baths, Use of Biological Cleaners, Aquatic Surgery, The Three Sets of Factors That Determine Livestock Health/Disease

Related FAQs: Medications/Treatments 1, Medications/Treatments 2, Medications/Treatments 3Dips/BathsAntibiotics/Antimicrobials, Anthelminthics/Vermifuges/Dewormers, Copper FAQs 1, Organophosphates, Epsom/Other Salts, Formalin/Formaldehyde, Furan Compounds, Garlic, Homeopathic Remedies (teas, pepper sauce, other shams...), Malachite Green, Mercury Compounds/Topicals, Metronidazole, Quinine Compounds, Sulfas, Treating Disease, Treatment Tanks, Medications/Treatments II, Treating Parasitic Disease, Using Hyposalinity to Treat Parasitic Disease, Garlic UseAntibiotic Use Marine Disease 1, Puffer Disease

Not a dye like Malachite Green... Hypoplectrus puella (Cuvier 1828), the Barred Hamlet.

Dipping Procedure        10/10/19
I couldn't find online but is a 30 minute bath in Methylene blue safe following a fresh water dip?
<... a bath, for marine fishes? Yes, in saltwater w/ Methylene Blue. B>
Re: Dipping Procedure     10/12/19

Thanks. I have a bunch of fish that were scratching at the gill area pretty consistent. Figured it was crypto or possibly flukes. Have the fish in QT and both copper and PraziPro didn't stop the flashing.
<Could be other source/s of irritation>
I was going to transfer the fish to a new QT tank but wanted to FWD them prior to going into the new QT tank. Some of them also look a little raggedy from either the copper or what's ailing them so was going to also give them a bath in Methylene blue.
<DO review Ed Noga et al.s works re sampling, checking under a 'scope. More
organisms are lost due to over and mis-medication than any other cause. B>

Quick note     11/18/18
Hi all:
I just wanted to let you know that I’m a writer for reef2reef.com, and I mention Bob Fenner (kindly) under “Methylene blue” in today’s article here: https://www.reef2reef.com/ams/keeping-your-marine-fish-healthy-part-2-the-reef-aquarium-medicine-cabinet.526/ 
I’ve asked WWM several questions over the years, and you folks have always been wonderful. (I even asked a question a few days ago.)
Warm Regards,
Cynthia White
Vancouver Island
<Ahh, thank you for your timely and pleasant note. Oh how I wish I could spend more time tide-pooling off Vancouver, ala "The Outer Shore" by Ricketts. Bob Fenner>

hi yall. I REALLY need your help real quick before I screw this up. Dips, baths for Angel, Wrasse     3/16/16
Hi guys-
<Hey Lis!>
I know ya'll are busy, but I thought I would still try and reach you. I'm getting both a big beautiful Melanurus Wrasse and a Singapore Angel fish this Friday. I was going to just give them a freshwater dip and put him in
my DT rather than QT them like I do all my other fish. What do you think of this idea?
<Am a strong supporter of this alternative protocol, for quite a few groups/families of fishes; including many Labrids. Do read here re adjuncts to dips/baths: http://www.wetwebmedia.com/dips_baths.htm
<Bob Fenner>
re: hi yall. I REALLY need your help real quick before I screw this up     3/16/16

Excellent! I can't believe you replied to me YAY! Okay I will read the article, and send all future emails to crew@wetwebmedia.com!!!! thank u so so much!!
<Heeee! Cheers dear. BobF>
re: hi yall. I REALLY need your help real quick before I screw this up. Dips/Baths      3/17/16

Ah okay, so I read the article on Dips/Baths- just a few more questions and I'm done- didn't see this in the article
1. other than temperature acclimation while still in their bag, do I drop acclimate them at all with water from my tank PRE=DIP?
<IF the temp. they're going in to is no more than 8 F. different, no need for temp. adjustment>
2. I'm going to have to buy the Meth Blue cuz I won't have time to mix it up myself. Can I find it at my LFS?
<Oh yes; commonly offered by its own name>
3. what's the AVERAGE recommended time (minutes) for a fresh water bath with Meth Blue? I know this varies, but what is the MINIMUM per say?
<Mmm; tres minutos. BobF>

Methylene blue necessary for acclimation?       10/10/15
Hi your websites great, so much useful info.
<We try!>
I've been reading your guide to acclimatizing new imports, everything makes sense and i am ready to trial your recommended method. The problem I have is I'm based in the UK and I can't seem to purchase Methylene blue to add
to the freshwater dip, is it essential to add the Methylene blue?
<Not required, but helpful. Ph and temperature adjusted freshwater is fine.>
Is there any other treatment that is available in the UK that I could use in place of the Methylene blue.
<Personally I believe in watching the animal at a dealer's for a week or so, making sure it's healthy insofar as you can
observe, with a deposit to hold onto the fish if needed. My favorite local retailer dips them as he receives them and again before he sells them to me, may want to ask for this service, which they should be happy/wise to provide. Chemical dips are possibly stressful and I consider them more of a prophylactic for suspect animals than a requirement.>
Thanks Chris
<Glad to be of use, please follow up with your results for others' edification and also read WWM's section on dips, it's pretty thorough. -EC3>
Re: Methylene blue necessary for acclimation?       10/13/15

Thanks for coming back to me so quickly.
<Now BobF; Don't know if Earl put this in my inbox....>
Sorry I wasn't very clear in my firs message, I run an lfs and am wanting to fine sop for new fish imported.
<Uhh; please read here: http://wetwebmedia.com/methbluefaqs.htm
and here: http://wetwebmedia.com/dipsadditvs.htm
Would just a freshwater dip be sufficient ?
<Uhh; let's have you scroll here: http://wetwebmedia.com/mardisindex.htm
Or do I need to get a treatment to add into the dip, if so any idea what I might be able to use over here in the uk ?. Thanks
<Right. Bob Fenner>

Sick fish, Betta, presumably Amyloodinium, Malachite, Methylene Blue  - 8/28/12
Hi Bob! I met you at SAS (Sacramento Aquarium Society) a while ago, and I asked you about disease treatments, and the use of malachite green. (I'm the kid that asked a LOT of questions) I have a Betta that I am sure has velvet, and the only med I have is malachite green. He has all the symptoms, looks like he's got gold dust on him, is lethargic, is flashing, (scratching) and isn't flaring at all and has a loss of appetite. This morning, I noticed that two more females are flashing, and looking slightly lethargic. One of them is breeding stock. I am debating the use of malachite green, as I am breeding for show fish. The fastest I can get Methylene blue is 5 days. I really don't want to lose any fish because of this, but I don't want to mess up the genes.
<I understand>
 So far, I've raised the water temp, added salt, and added banana leaf tea to the water, along with some stress coat. Is there anything else I can do?
<Water changes after each treatment. Please read here: http://www.bettafish.com/showthread.php?t=57845
 Also, can I use Flubendazole to treat it?
<Mmm, no>
Also, would  Metronidazole work?
<It might, but I'd stick w/ just one med.... The Malachite at this point>
 Are there any ways I can prevent it with my other fish, other then not contaminating them, and separating them?
<Sure... isolation of new stocks is always a good idea>
 Will Methylene blue kill my plants and snails?
<Mmm, is a bit hard on these, but no where near as much so as the Malachite>
 Can plants and snails carry velvet?
<Not carry but anything wet can transfer this Protozoan>
If they do, is there any way to cleanse them
without killing them?
<Isolation for a few weeks should diminish the pathogenicity sufficiently>
Thanks so much for your time!
<Welcome Josh. Bob Fenner>
                     P.S. If there's any other med I can get, please tell me!
Re: Sick fish

So far, I haven't used malachite. Do you think giving the fish a bath in it will damage it?
<I wouldn't do this>
 Also, I read that velvet will die within 24 hours if it cannot find a host. Should I just keep my tank empty for 3-5 days, or more?
<A couple weeks>
I've darkened the tank, will that help?
<Some folks say so>
 I am considering taking all of my plants, (Italian Val) out, and keeping them outside. Can they take 60 degree water?
Can Malaysian trumpet snails take 60 degree water?
<For a few days, yes>
 Thanks so much for responding!
<I remember being young still. BobF>
Re: Sick fish

Thanks again for your time! Do you think you'll be speaking at SAS again?
I enjoyed your talk!
<Ahh, I do hope to come back... the gap from last time (eight years) was too long. Cheers, BobF>
Re: Sick fish - 8/28/12

I guess I'll have to talk to the president about you coming back. It was a really good talk.                                                          Josh
<Ah, good. Thank you. B>
Re: Sick fish, Betta     8/30/12

Sorry to have to ask you another question already, but suppose I spilled, let's say an ounce of Methylene blue into, hmmm, about 10 gallons of water with Betta fry, and after taking out a lot of water, the water is still blue, what bad things could I expect? How could I prevent these bad things?
<Not likely a problem. B>
Re: Sick fish, misc. FW, child      8/30/12

The people on fishforums.com said that it may cause cancer,
<... Methylene Blue? No>
use up all the oxygen in the water
<Actually aids in oxygen transfer>
, and raise the ph. I think I'll trust you though as I have met you, and found your info true so far. I don't want too much in
there, as I want good bacteria in there. Would putting a carbon filter in there be a good idea?
 How do I tell if it's activated carbon?
<One way, by activity... removal of the blue>
 Another question I have, which isn't related to Methylene blue,  is about my infusoria culture. I have seen little white worms on the sides of the jar.
Is that good food for my fry?
<Maybe. B>
Re: Sick fish     8/30/12

How do I tell if they're good? The are the perfect size for my fry.
<... the bioassay is most likely profitable here. Try them and see>

Re : fish sickness inquiry   8/25/11
I wanted to know how much Methylene blue should I put for a 60 gallons?
<The standard dosage is 2 ml of 1% Methylene blue solution per 10 litres of aquarium water.>
How long will the color stay?
<A few days.>
is it very dark?
<Not especially.>
does it reduce the oxygen in the water?
<Not substantially.>
<Cheers, Neale.>
Re : fish sickness inquiry
I have used Bactosan yesterday to clear the water from food, can I use today Methylene
<Probably. I'm not familiar with this medication, but it doesn't sound like something that will react with Methylene blue. Try it and see. If your cichlid reacts badly, then do a quick 50% water change, ensuring that water chemistry and temperature stay constant. Do not feed your fish while medicating! Wait at least 3-4 days before feeding your fish, and then do so SPARINGLY! Cheers, Neale.>
Re : fish sickness inquiry  8/27/11

hi, the color of Methylene blue has completely disappears in less than a day.
I have no carbon in the filter, only ceramic and stones. Also I forgot to mention that I have upside down catfish, are they harmful?
<Methylene Blue should not harm catfish. Cheers, Neale.>
Re : fish sickness inquiry  8/27/11

I took more picture this morning before putting the Methylene blue. there
is some blood where the scale is out. What is this sickness called?
<Not sure. Could be physical damage, maybe with a secondary bacterial infection is in the wound.>
Is Methylene Blue the solution?
<Maybe. It isn't very strong. But it will help a bit. Anti-Finrot medications, e.g., eSHa 2000 in Europe, would perhaps be better.>
I have put today 44ml of Methylene in my 230 litres aquarium, how long should I keep it before I do the water change.
The water color is not deep blue and after hours it looks lighter.
<Cheers, Neale.>
Re : fish sickness inquiry  8/27/11
<... 12 megs of pix... we only accept a few hundred per... and you need to run your writing through a spelling/grammar checker before submitting it>
I took more picture this morning before putting the methalene blue. there is some blood where the scale is out. What is this sickness called?
Is Methalene Blue the solution?
<... No>
I have put today 44ml of methalene in my 230 litres aquarium, how long should i keep it before i do the water change.
The water color is not deep blue and after hours it looks lighter.
<... learn to/use the search tool on WWM re this species health and Methylene Blue use. Bob Fenner>

Good morning..... CP, Methylene Blue uses... reading  2/11/11
Hey crew, I am having pretty severe troubles at this point in time and was hoping an expert could help me out. I just (as per the recommendation of Mr. Fenner) purchased Chloroquine Phosphate. I found it at a place called fishchemical.com (Fishman Chemical, LLC) and I am beginning to wonder if this place is legit. The smallest amount I could get was 1 kilo for $125 plus shipping.
<You don't need a kilo!>
Has anyone ever heard of this company?
<I have>
If so, are they real and legit?
<They are, but I'd order from other another supplier where I referred you>
What's causing my concern is the fact that not a single stitch of literature came with this compound in regards to dosage....shady. I am getting all different results when I Google AND when I search the forums on WWM...any ideas?
<Yes... stick w/ WWM... my input comes from Ed Noga... his new book, he and I were dorm-mates at the Fish Health Conf. last year at UNE. His referencing is impeccable>
Do you think it may be the same dosage as that of Quinine Sulfate? I just want to find an accurate and solid dosing schedule.
<... for CP, 10 mg/l, or 40 mg/gal... every five days for four treatments for Crypt...>
Any input on this would be great. Lastly, I have a question regarding Methylene blue. Is it possible for a fish to overdose on this Med?
<Almost impossible>
It seems. every time I. use this during a Ph adjusted freshwater dip (10 min), my fish seem to have erratic/jerky swimming and constant rapid breathing for a full 24 hours afterwards. I dosed about 9 drops in 3.5 gallons of dip water. Bob states in his book under the "treatment" section that its very hard to overdose on MB.
<This is so. There is something else, artifactual perhaps in the dipping process, not the MB>
The Med itself and the fish have a very broad range of toleration. If the dip water Ph is around 8.0 and the temp is the same as display tank, what else could be causing this consistent rapid breathing strange behavior?
<Not really, no. The act of being chased, netted, lifted from the water though... is extremely stressful>
Thanks so much folks!
<Welcome. BobF>

Quinine and Methylene Blue 5/19/10
Dear Bob and Crew,
Thanks again for the your tremendous commitment to the dailies. Even when in Egypt- wow!
<Now back, mostly>
Just a quick question today. I am making an order from National Fish Pharmacy for Quinine Sulfate and Methylene Blue and wanted to know if you recommend any other medications to have on hand. I've learned that speed is essential in curing diseases and that fish lives can be saved by having the proper meds at home.
<Mmm, others have such recommendations, not I. See here re Tim Hayes
On a quick side note, according to Drs. Foster and Smith, the Kordon Methylene Blue product states that is to be used for freshwater fish. I know that you've stated countless times that this can also be used for marine. Is there another Methylene Blue product that you recommend for marine?
<Any Oxalate free formula, supply will do>
Thank you so much and have a quick safe trip home!
<Be chatting, BobF>

Methylene blue! FW use, FW Clams...   3/23/10
Hi I've recently treated a sick fish with methylene blue,
<Largely recommend against this unless you have no other options. Can be used to treat fungal infections; somewhat less reliable against external bacterial infections. But can, will stress filter bacteria and also stains just about everything, including the silicone sealant holding your tank together.
<<Mmm, Neale... are you thinking of Malachite Green here? Methylene Blue rarely disrupts nitrification, and doesn't stain greatly. RMF>>
Re: methylene blue! 3/24/10
Hi Bob,
Yes, quite sure. Just double-checked in 'A-Z of Tropical Fish Diseases and Health Problems' and 'Interpet Manual of Fish Health' and they both say the same thing. Of course, may depend on the concentration and usage, so your
mileage may vary!
Cheers, Neale
<Thank you Neale... I suspect I've had "too diluted" experience here. BobF>
 Can kill plants and invertebrates, too. Basically, old school medication with few/no redeeming features.>
I have put it into a separate tank as I have a fresh water clam
<This will likely starve to death unless you are feeding at least 4-5 times per week on suitable filter feeder food (e.g., as sold for feeding marine clams and tube worms). Contrary to popular "marketing" these clams don't
scavenge, they don't eat algae, they don't filter food from the water, and they don't live long in aquaria. Complete waste of money, really. Will usually starve to death, and when that happens you have a great lump of seafood rotting in the aquarium.>
in my main tank and I was unsure if the methylene would damage it.
<Correct assumption.>
Could you advise me weather or not to treat my main tank as well as the fish that is now separate.
<Depends what you're treating. With methylene blue, because it can, will kill filter bacteria it is normally used in the hospital tank. DO NOT use in your display aquarium. Use Zeolite to filter the hospital tank. For a small to medium sized fish, a simple box filter filled with Zeolite changed weekly should do the trick.>
Also the fish that is in a separate tank has a hole/ulcer on its side and the pet shop could not diagnose this they thought it could be a bite from my other fish on it could be a disease that could in the future attack my other fish.
<"Ulcers" can mean different things. Could be Finrot, could be a bite from an aggressive tankmates, could be hole-in-the-head. Need a photo and some idea of the fish and its surroundings (tank size, water quality stats.) to answer this.>
Could you advise me on this to and whether my clam is going to be affected by any of these diseases or the treatments?.
<Almost all medications other than antibiotics or salt can, will kill molluscs including clams.>
Thanks for your time
Miss Muir.
<You're welcome. Dr. Monks.>

Methylene Blue - Is it safe for a QT tank?  9/27/08 Greetings WWM Crew, <Mike> After reading the articles and FAQs on Methylene blue (MB), I have a rather simple question: Is MB safe to use in a SW QT tank? <Very> I have read conflicting information. The CMA and this website only mention its use in a FW dip, but I have read accounts of is being used when shipping fish. Other on-line resources state that MB is to be used in FW only. <It's been a long time since I've seen Methylene Blue used in shipping marines... some folks, businesses do use it in freshwater applications... in both to reduce light penetration (calm the animals before being boxed) and improve DO> I have a 55g QT tank, I use PVC piping to provide a shelter for the fish, and use about 0.25" of regular "play sand" for a substrate (It is disposable after QT is finished) 10 - 25% water changes are done daily. I use a canister filter for water filtration\movement, and a sponge filter for biological (kept in the sump between uses.) I always give new acquisitions a FW dip with MB, followed by hypo-salinity (1.015 - 1.017) in the QT tank, slowly building it up to 1.025 near the end for the QT period. I would like to add MB to the QT tank at least during the first few days, Partially for its mild antiseptic\oxygen carrying properties, and secondly because I have noticed that new fish settle down and adapt better if the water is "darker". <Worth trying. I don't think there is much chance of any serious downside/s here> Thank You, Mike <Welcome. Bob Fenner>

Re: Acclimation procedure  3/30/08 Hey Crew, I know that I, as well as many other people, rely on you guys for help. You supply us with a wealth of info and from time to time are given some thanks. I just wanted to drop a note to say you guys are providing a great service for us fish/reef geeks. I have read and followed many of your recommendations, (including Bob F), and must thank you under separate cover. A recent example that demonstrates my gratitude is Bob's recommendation regarding acclimation procedures. I have utilized blue meth combined with aqua nova on the acclimation of all of my new fish additions and thankfully have had no problems since. Just wanted to thank you guys for the education and the great service you are providing. As always I look forward to future correspondence. Frank <Thank you Frank... for taking the time, making the effort. Your kind words are encouraging. BobF>

Methylene Blue 03/04/2008 Good afternoon Crew! Just a quick question. I purchased a Pygmy Angel and Flame Hawkfish over the weekend and plan on picking up this week and placing them in my QT after a fresh water/Methylene blue dip. Is the Methylene blue safe for the Dwarf Angel? <Yes. Very safe for all> I vaguely remember reading on your site that Methylene blue is not safe for all fish, but could not remember and could not find if this included the Dwarf Angel. Thanks as always! <Please read here re: http://wetwebmedia.com/methblueart.htm and the linked FAQs file above. Bob Fenner>

Re: sick clownfish? Now, Dips/Baths...   2/21/08 Crew, This really isn't an area have I gathered much experience in, having my LFS/wholesaler QT and treat for me before I collect - feeling slightly inadequate, can I ask one of you guys with the relevant experience field? Mike I, WWM <Okay. RMF responding> Mike, I read your recommended links. I am a little confused. In using Methylene Blue do you utilize fresh RODI water, (since the article does say fresh water but later lists "new or system water")? <For dips? New, treated water... RO/DI is fine if aerated... otherwise has no oxygen...> {I guess you could mean net of salt}. What is the prescribed dosing, (Meth vs. gal of RODI)? <Just "very blue"... the stock concentrations vary... But/and Methylene Blue is very safe to use at high dosage> "about ten mils of this solution used per approx one gallon of dip" does this mean 10 milliliters? <Mmm, maybe... again, given commercial concentrations vary... Just so blue you can't easily see the bottom of the container...> The article also mentions that you could purchase pre-made, where might one find this? <Pre-made what?> Lastly, do you recommend dipping as part of the acclimation process. <I do... commercially... for home hobbyists, buying local stock... quarantining ahead... or in transit, such dips/baths are a judgment call...> In other words when you bring a new fish home from the LFS you would dip first in a Meth solution that is the same temp and ph of your main display or would you first acclimate the fish by lets say the drip method for a couple of hours. <Either first, enroute to quarantine, and/or on the way from there to main/display tanks> This way the ph and water temp of the shipping bag is close or equal to your display water and then dip in the solution? <Mmm, very important to respond to this clearly, completely: Best to measure said pH, temperature... IF the pH is much different (esp. higher in your system than the shipping water) OR there is any discernible free ammonia in the shipping water, best to match the pH or have it slightly lower (this is mainly a commercial, importer concern... or with folks moving, buying aquatic life that is/has been bagged for hours duration... And "rinse out" the mixed shipping/transit water, with that of the system pH over time... Covered under "Guerilla Acclimation Techniques" on WWM> {2 step process/acclimation followed by dipping}. Don't you feel that the fish is stressed moving from the LFS to the shipping bag to the acclimation procedure then to dip and QT? <Yes> Only to be moved at a later date into the main display. Can the fish survive all of this? <Oh yes... and you can be spared (along with other livestock) the troubles of bringing in pests and parasites...> I understand that if we don't take precautions then we put the entire main display tank at risk & of course the fish if it has any disease. But I am just wondering if all these procedures adds to the stress of the animal and in and of itself can increase mortality rates. <Is a concern... as you well voice/state... Hence my comment re "judgment calls"... Not all livestock can stand, nor benefits from such dipping/bathing... IF the animals are too weak, best to accelerate their placement (in quarantine), allow to "harden" (rest up)... and consider such prophylactic measures on moving further> Thanks for all the info, I look forward to your reply, Frank <Welcome. Bob Fenner>

Re: Crypt. and starting over Dear Mr. Fenner, thank you for your response to my last Email. I did review info on dips/ baths and Crypt in your book as well as on the website. After several bad decisions what I'm left with is multiple Crypt casualties and a fishless 60 gallon FO tank which has been treated with Cupramine. I plan at this time to let the tank go fallow. I have raised the temp to 85 degrees. Should I remove the copper with carbon at this time or let it ride until the end. <Leave as is... it will "complex", be gone in a few days to weeks> At this temp would four weeks be enough time rid the tank of Crypt cyst forms. <... see WWM... the longer, the more sure> Lastly, I believe my initial outbreak of ich began because of a freshwater (adjusted for temp and ph)/Methylene blue dip which was too short in duration, about one minute. Because the water turns so dark with the Methylene blue I feel I am unable to monitor the fish for agitation. Two quick questions then I'm done. First, if the fish is not jumping and breaking the surface can I wait five minutes before removing from the dip solution and adding to my QT. <Better to not "blue" the water to such a degree... and watch for overly labored breathing...> Last, can I leave the fish netted in a large net during the entire dip or dose this increase stress. <Is fine to leave in a net... I and the fine folks I worked with at our stores did this for tens of thousands of specimens...> It would certainly limit my stress. I'm determined to reestablish my tank and not leave the hobby and I have appreciated all of the valuable information on your site. Thank you, Mark Conley. <Good luck, life to you Mark. Bob Fenner>

Pharmacy grade methylene blue  8/5/07 Hello Crew. I'm looking to get some pharmacy grade Meth blue from my local pharmacist (who is also a customer) for dipping new arrivals. He can get me in two types of it. One is 1% solution at $25/100ml. The other is crystals which run $60/25 grams. My math in figuring out stuff like this is horrible, so my questions are: Is the 1% solution proper for aquarium dosing as per the Guerrilla Acclimation? <Yes> Which of the two types would be better to use? <A/the pre-mixed... But, I hasten to add that you don't need this grade... tech. will/would do... any as long as it's oxalate-free... And at a considerably cheaper price> How much solution (water?) would I mix the crystals in to get the desired concentration? <I would NOT make your own unless you knew enough to do the expanded notation to figure out the concentration from the MW... You will too likely contaminate the solution, mis-store it... Too much trouble for what it's worth... Buy an aqueous solution> Thanks again for the great advice and site. Regards, James Foley Thunder Bay Aquascapes www.tbaquascapes.com <Welcome. Bob Fenner>

Re: Pharmacy grade methylene blue 8/10/07 Thanks for the reply Bob. But I now have another question. I was looking for pharmacy grade because of this quote in the Guerrilla Acclimation article. "Also thanks to Dr. Bob for urging the emphasizing that only "Pharmacy Grade" Methylene blue has the desired therapeutic properties." <Ah... Dr. Bob Rofen of Kordon-Novalek> So any Methylene blue will do as long as it's oxalate free? Or would pharmacy grade have a more significant impact? Regards, James Foley Thunder Bay Aquascapes www.tbaquascapes.com <Again, tech. or reagent grade w/ no oxalate will be fine. BobF>

Methylene Blue Question 7/10/07 Dear Crew, <Andy> I have started to use Kordon's Methylene Blue as an additive when I dip my new purchases before putting them in QT. I have noticed something very strange with the last two fishes I purchased--a Brown Combtooth Blenny and a Royal Gramma. I concocted a pH adjusted FW dip and then added the MB to the water until it was a deep royal blue (I did not add as much as instructed on the label for dips (5 tsp for 3 gallons), as I thought this seemed crazy). In any event, within about 1 minute both fish ended up looking like they had rigor mortis. Arched spines and gaping mouths--no movement. The first time this happened (blenny) I immediately removed him to a saltwater holding tank--he immediately revived like nothing happened, so I put him back in the dip for another 2 minutes--same thing. Same reaction with the Royal Gramma, but I decided to push the limit and keep him in the dip for 4 minutes. As with the blenny, as soon as he was placed in the QT, he revived. Both are doing well. Is this normal with MB use? <Andy, I'm not a fan of medicating fish that do not require it. The freshwater dip is enough shock to their system without creating more. I'd just stick with the freshwater dip, and/or better yet, quarantine the fish before adding to your main display tank. And yes, this could be normal depending on the fishes health at the time of treatment. James (Salty Dog) <<RMF is of decidedly a differing opinion... MB is extremely safe... and useful>> Andy

Re: Methylene Blue Question 7/11/07 James, I do quarantine, but I always give a FW dip before putting them in the QT. Not to be rude, but your response goes against everything in Bob's CMA and WWM. He heartily recommends pH adjusted freshwater dips with formalin or MB in transit between shipping and QT and between QT and display. <Andy, I do realize this, but as I mentioned, it was my personal feeling/opinion. I've used freshwater dips on occasion years ago, but I've found that if the fish is weak/stressed to begin with, I've caused more harm than good. It can be difficult to identify stressed fish in a dealers tank, as stressed fish generally hide, and dealer displays offer little or no cover in which to take refuge. I'm not saying I'm against FW dips, but I prefer quarantine and dip only if I feel it is necessary. James (Salty Dog)> Andy Bulgin Re: Methylene Blue Question 7/11/07 Understood. Thanks for the follow-up. I didn't mean to come across as a jerk--just noting that CMA advocates for dips. <Did not read you as a jerk, just a very observant person. Again, keep in mind that this is just my personal opinion. I'm not saying not to do the FW dips.> I just thought it was odd that two separate fishes showed identical behavior when exposed to MB. <Why wouldn't they, they are both exposed to the same medication. James (Salty Dog)> Re: Methylene Blue Question 7/12/07 Because MB is touted as an extremely safe additive and, as such, I would think it should not have produced the response about which I asked. See http://www.wetwebmedia.com/methblueart.htm: <You are misreading me. I didn't say MB is not safe, just stated my practices. MB is very safe, I just do not use it.> "Tolerances/Dangers: Other than the contraindications stated above (not to be placed in long term contact, not with live plants)... Methylene Blue is relatively non-toxic in a very wide range of concentrations. Often, aquarists are advised to "just place as much as turns the water very blue"... Cloze: This being stated, there is no harm in having Methylene Blue as an addition... or using it where it is best... as a dip/bath additive or in fungal prevention in freshwater fish culture. . .." <In agreement, but I cannot give you an accurate answer as to why your fish reacted as such, might very well be from the water parameter change. Fish will have different tolerance levels of FW dips. When the fish appears stressed, I would remove it from the dip. James (Salty Dog)> <<Highly likely there was "something else", other than the MB going on with this situation, water, fishes... RMF>>

Methylene Blue   7/2/07 Dear WWM Crew, My Betta has been lethargic for a couple weeks with no outward signs of disease. I started treating him with daily doses of Pimafix and Melafix. I have also now noticed a couple of white specs on the side of his head. I am planning to give him a dip bath in Methylene Blue. Is it safe to do this while I am treating him with Pimafix and Melafix? Jean <Hello Jean. I'm a bit Old School about Pimafix and Melafix. I think they're massively overrated, and have heard far too many stories of people using them *instead* of traditional medications and their fish still getting sick. While they may well be excellent general purpose antiseptics that help keep external wounds clean, I can't see how they can treat internal problems. Whitespot, for example, lives under the skin and is isolated from any medications, which is why most treatments kill the free-living "baby" whitespot parasites rather than the adults you see on the fish. So my recommendation would be to go ahead and add some standard Methylene Blue to the Betta aquarium to fix the whitespot (as this sounds like what you have). Stop with the Pimafix and Melafix while treating the aquarium (mixing medications is somewhat unpredictable). Once the whitespot is fixed, you can go back to doing your Pimafix and Melafix routine, though to be honest you should need either if the aquarium has a proper filter, good water quality, etc. Using Pimafix and Melafix as a standard addition to an aquarium is essentially admitting the water quality in the tank is so bad its filled with pathogenic bacteria. Think of it this way: it would be as if you let your house fill with garbage and filth, but sprayed it with antiseptic so it'd be safe to live in. If you just cleaned the house and installed plumbing, you wouldn't need the antiseptic! This is one reason I abhor those horrid "Betta bowls" you see sometimes, with 1 gallon of water and no space for a filter. These force people to keep Bettas on what's basically a live-support level maintenance regime of constant water changes and additions of antiseptics and other supplements like salt. If people just treated Bettas properly and gave them a nice 5 gallon tank with an air-powered sponge filter, problem solved: nice, robust, easy to keep fish. The irony is any money saved on a Betta bowl compared to a sensible aquarium is more than frittered away over the long term on all those silly additives! Cheers, Neale.>

Re: Methylene Blue -- 07/03/07 Dear WWM, Thanks for responding with so much detail to my previous e-mail. It's very much appreciated. Just one question; if I add Methylene Blue to my tank, won't that kill the good bacteria? Thanks again, Jeannie <Provided you follow the instructions supplied with the medication, Methylene Blue is harmless to filter bacteria. Cheers, Neale.>

Ammonia Toxicity and methylene blue   5/9/07 Ok, I need the opinion of a marine biologist. <Well, have labeled myself as a pet-fish ichthyologist at times... Friendly neighbourhood one at that> Is there any benefit of using methylene blue in ammonia toxicity besides the fact that it will treat any concurrent nitrite poisoning and methaemaglobinaemia? <IMO yes... slight anti-microbial effect, enhanced dissolved O2, darkening of the environment reducing stress...>   If there is such a benefit then what is the mechanism of action in helping with ammonia toxicity?   <Perhaps ancillary nitrification through higher DO alone> We are having a discussion about this on another forum and I need an expert opinion.  I've done a search on the net and there are vague references to using methylene blue in ammonia poisoning. Thanks, Larry <Perhaps a go at Hoar and Randall's tomes on Fish Physiology... Bob Fenner>

Freshwater dips with Methylene Blue 5/1/07 Hi there,  Whomever is polite enough to respond to my question. <Hello> I have been doing some reading, probably not as much as I should, but at least a fair attempt at it anyways, on Ick. From what I've read Bob himself is not really an advocate of hyposalinity as a treatment. And I believe I understand his take on it being a result of inconsistency in the results. However freshwater dips seems to be a preferred method of treatment when used with Methylene Blue.  <FW dips are helpful but rarely a treatment in and of themselves.  The problem with hyposalinity is that it needs to be closely monitored.  If the SG gets too high it is ineffective and too low and it get too hard on the fish.  However with some fish that are very sensitive to copper it is a viable option.> There seems to be those who advocate one or the other, but not both. <Some, not me however.>  And those who advocate hypo definitely will not budge towards FW dips, basically because the stress the dips can cause on the fish at hand. <Yes, but some people like to ignore the fact that anything but natural SG is stressful.> However it is my belief that hypo can also be stressful in some fish. And is a long 3 week duration of being in a specific gravity relatively close to freshwater as it is. The stress of the dip is mainly derived from the sudden change in specific gravity, correct? <Yep, and pH and temperature shock if not properly prepared.>   Methylene blue helps this stress out, correct? Wouldn't the dip be a shorter duration of stress? <Yes, but a higher stress level, if a fish is very sick this shock can be fatal, but in reality only in fish that probably not have survived anyways.> This may sound like a crazy idea, and tell me if it is. I am not really wanting to attempt this but just curious about possible methods of providing total elimination of the parasite from an infected fish. Because a single freshwater dip with Methylene blue will not totally eradicate all crypt, what about a series of these dips, say like one a day for a period of time, each time placing the fish in a different QT using aged, matched SW. To prevent reinfection from the Qt the fish was previously in. I don't mean necessarily a whole string of tanks, 2 should do. Sanitizing the tank the fish was previously in, then making it ready for the next dip.  <An very good way to do it, but beyond most people's ability and effort.   Steven Pro's excellent article has a bit on this method.   http://www.reefkeeping.com/issues/2003-08/sp/index.php .> So if you don't think I'm nuts for this, do you think it's a viable option for a treatment? <Absolutely.> How many dips would it take and for how long for it to be an effective treatment to provide complete eradication? <Probably looking at a couple of weeks, although on your first attempt I would probably go a little longer.>  Would this be more stressful to the fish if done correctly? <Yes, would be stressful, but is all relative.>  Matching all water chemistry, avoiding nets, etc?  <Any time you net a fish it is stressful, and you do it often in this method, so there is one downside.> Thank you so much for your patronage. You do not know how much help you wonderful site is to this aquarist. (and countless others) Charlie <Thanks> <Chris>

Methylene blue  - 03/02/07 Hi there <<Hello!>> I have a 4cm black moor in my 10g tank and 3 days after buying it, it developed white spot - I'm assuming it had this when I bought it and I just didn't notice. <<Perhaps.  What are your plans for tank upgrade?>> So I put some methylene blue tonic in the tank to treat the whitespot, and the people at the pet shop (another one - I didn't trust the first lot after the sick fish) said to replace the airstone once the fish was well and the blueness would come out of the water. <<Methylene blue is not the proper medication to treat Ick. There are much better treatments for this.  You biofilter is likely gone now as well from dosing the main tank.  I'd get on large water changes, adding Bio Spira and mature filter media from an established tank, and add some activated carbon to the filter to help remove the medication.>> I have an under gravel filter but not a carbon filter as such. The problem is that adding an air stone has made no difference, <<No, it wouldn't.>> And my healthy-looking moor is now swimming around in blueness. I've done two 50% water changes over the past 2 days in an attempt to clear the water but it's still very blue. I don't want to tip all the water out and start again because I don't want to kill or stress my fish, but I am quite keen to get rid of the blueness -any ideas? <<See above.  If you have nowhere to add carbon (a small HOT filter will do), keep up the water changes.  Please note that the Methylene Blue will permanently colour the silicone in the joints of your tank.>> Would tipping all the water out and starting again be that bad given that the methylene blue probably killed my biofilter anyway? <<Usually does not. RMF>> <<I recommend large water changes, not total water changes.>> Rose <<Good Luck Rose! Lisa.>>

Methylene Blue as a Marine Ich Cure? (Nope) -- 11/01/06 Hi guys, <<...and Gals>> I have a small question. <<Okay>> If Methylene blue is a good anti-ich in fresh water why can't we use it to get rid of ich in salt water tanks? <<I don't agree that Methylene blue is a good ich treatment in freshwater, and I certainly wouldn't recommend it for ich treatment in saltwater...ionized copper is much more effective/the more appropriate treatment>> Is it poisonous for invertebrates or is there any other reason why no one uses Methylene blue in the salt water trade? <<It has low toxicity (Best used as a bacterial/fungal 'preventive' measure.  Commonly used re to help protect fish eggs during incubation).  The reason it's not used as an ich cure in the marine trade is because it is not effective as such>> Best regards, Akila <<Cheers, EricR>>

Use of Methylene Blue in Freshwater Dip for Dogface Puffer  - 10/28/06 Greetings, <Hi there> I'm involved in recovery from a disaster of my own making.  Having been in the hobby (fresh water and more recently marine) for a number of years and an avid supporter of isolation tanks <A good term> for new livestock, I violated protocol and ended up introducing marine velvet in a 125 G FOWLR.   Why?  Bad judgment.  A mail order specimen of a pink tail trigger shipped larger than I expected, too large (I thought) for the 20L isolation tank I've used for years.  Though he looked completely clear, obviously, he wasn't.  Velvet is a nasty and ruthless disease and it killed all but one of the fish in that tank within a week.  The sole survivor was a Picasso trigger.  I've never had a disease ravage a tank like that, fresh or marine, and I know better than to do what I did.   Took me awhile to recover from what I'd inflicted on those other fish, but I'm going to give this another shot.   The FOWLR tank has been fallow for 2 months now.  Parameters are good.  My first candidate, a dogface puffer, is arriving tomorrow.  His quarantine tank is set up, temp adjusted, proper salinity, etc.  He has a fresh water dip awaiting him as well.  The dip is Ph adjusted, heated properly and equipped with air stone as RO water is used.   In four weeks, he is to be my canary in the 125.  With a bit of luck, a very long lived canary.  Perhaps I should consider a larger quarantine tank at some point.  I hate to give up that 20, though, since you can do a 50% change with just a couple of buckets of water. My question is this.  Many of the threads on this site recommend use of Methylene Blue as an additive to the FW bath for both oxygenation and anti-whatever (parasite, bacteria, etc). <Mmm, yes... and light-reduction as well>   However, I seem to remember that dyes can be rough on scaleless fishes from one thread but darn if I can find it again. <"There are dyes and there are dyes..." Metal dyes by and large should be avoided... Methylene Blue is not one of these>   Should I use the dye, resort to weak formalin or just use the fresh water alone on this specimen? <Let's see... with a nod to remembering that many people will read/use this... If you were in "the trade", and/or handling a bunch of specimens (even Puffers), I would use dilute formalin in the mix here... But for the vast majority of hobbyist circumstances/occasions, Methylene Blue is all I would add... very safe, effective. Formalin... a toxic bio-cide...>   I have not used dipping as part of my protocol in the past and I'd like to get this correct.  Secondly, I'm curious as to whether repeated dips (3 - 5 over 7 days) are advisable during quarantine or should this practice be used only during treatment of a suspected infestation? <Much more of the latter. There are easier considerations one can make re the apparent and real benefits of re-dipping versus the damage, stress...> Many thanks for your time and the information that you've compiled for our use.  Our critters are most rewarding when happy, well fed and disease free and you help keep them that way. <Thank you. We are in full agreement here. Bob Fenner>

Achilles Tang - Specimen selection and use of FW dip with Meth Blue    7/19/06 Hello, <Hi there.> I have a few questions if you don't mind.<Sure, no problem.> I have a 100g reef system with tons of mushrooms, a torch coral, a frogspawn, two devils hands,  some feather dusters a BTA. For fish I have a yellow tang, purple tang, one powder blue Chromis and a clown goby. Oh, and a bunch of snails and hermit crabs. I want to add another fish to this mix but am wondering what. I just lost my sohal tang <So sorry to hear that> that just disappeared over the weekend, but he was doing very well temperament wise with the other tangs. <There is a good chance he was not getting along as well with the other 2 Tangs as you thought he was.> I would like to add an Achilles tang, but I know this fish has its troubles. <Yes it does and to be honest 100g is really to small to house more than a single Tang. I would suggest you leave well enough alone and choose another species.> How do I know that I have a good specimen? Please have a look at this article. It discusses specimen selection '¦ http://www.wetwebmedia.com/acanthurTngs.htm.> I read the site and you say the best come from Hawaii and are caught at night. How do I request a fish like that at my LFS?   <Hmmm, start by asking. I am pretty sure they will not be able to tell you what time of day the fish was caught, but you may be able to get information about it's source.> Also, what is the best dip to use before putting him in the tank? Methyl? Also, what amount of Methyl do I use with the freshwater and how much water do I use for the dip? Please help if you can. <My personal preference is not to use chemicals or medications prophylactically, so I would not recommend the use of Meth Blue. I would however recommend quarantining new arrivals. Hope this helps,  Leslie>

Methylene blue  - 1/30/2006 Mr. Bob Fenner I understand that you recommend a freshwater dip with Meth. blue before the qt. You also mention the practice of the use of Meth. blue, with 1/5 of the dip dosage, during 2 or 3 days, in the quarantine. The question is if this a normal/ prophylactic procedure or instead, an exceptional one ? <Mmm, more normal than exceptional. This is to say, it/both are "standard operating procedures" in business, with many hobbyists> I have experienced in the last 2 months a lot of fish losses (5) in qt with just the arrival dip. After 8 or 10 days in the qt they become infected or infested and die. So I think that would be good if the use of a prophylactic product during the quarantine could weak the parasite resistance more than the fish's. Is Meth. Blue the right choice for this? <Is a very safe, useful material> Other product ? Formalin? H2O2 ? <Formalin is too toxic, dangerous, peroxides too transient for most uses> When treating in the qt and performing an water change the new added water must have the same remedy concentration ? <Best to try keep these about the same, yes> Thank you very much for your help Flávio <You're welcome. Bob Fenner>

Freshwater Dips with Methylene Blue  9/17/05 I've been able to use Bob Fenner's method of freshwater dips with the addition of Methylene Blue very successfully in my first marine fish only tank of 110 gallons. The only problem I've had is monitoring the progress or lack thereof of the fish I place in the dip. The solution is typically a dark navy blue color and unless the fish starts trashing about near the surface of my gallon bucket I have no idea on how it is tolerating the procedure. Any suggestions on how a fish can be better monitored during the emersion process in this opaque dip so that signs of distress can be rapidly identified? I had tried just leaving the fish in a large net while in the dip bucket but even then I often have to lift it out of the dip solution to check on it's status and I feel that this just adds to the trauma of the process for the animal. I know this most sound like a silly question but any suggestions would be really appreciated. Thank you. John Ragone <Mmm, I would just use somewhat less Methylene Blue... enough to still see the fish/es while dipping/bathing. Cheers, Bob Fenner> The Big Blue Dip (Methylene Blue Dips) 7/29/04 Bob, <Scott F. in today!> I just read your article (The Conscientious Marine Aquarist: Dips/Baths) and had a question about the Methylene Blue dip procedure.  I've read articles instructing FW dips for as long as 7-8 minutes (I've done dips that long w/o any additives). I don't know what concentration your recipe provides.  Kordon says no longer than 10 seconds for a dip using their MB at 50ppm. Assuming the fish is not reacting adversely, how long do you recommend as  a baseline duration using your MB/FW mixture? Thanks, Brian <Well, Brian- I use Kordon's Methylene Blue in my dips (have for years), and my application of it is hardly scientific: I just use enough to get the water a nice deep blue, and I dip my new arrivals about 3 to 5 minutes. I've never lost a fish in a freshwater dip such as this. Now I'm not saying to just dump it in there-well, maybe I am...But seriously, I have not had problems. Yes, it can be a bit scary at first, but if you observe the fish carefully, it's an effective technique. If you're talking about using Methylene Blue in saltwater, then it's really not a problem, either IMO. Hope this helps. Good luck! Regards, Scott F.>

Methylene Blue Dip (Salt Water) 6/14/04 Have no quarantine tank and collect my own specimens from the wild. <Dips or not, you are taking a big risk here.> Have read Methylene blue mixed with fresh water (Is this right for marine systems, can I use rain water with pH and temp same as tank or should I use tank water?) is the next best thing.  Is this so? <Methylene blue is a nice adjunct to a properly conducted FW dip.  I would suggest using filtered tap water pH and temperature adjusted to match the aquarium water.  I generally recommend dips as a prophylactic measure before placing the fish in quarantine, not as an acceptable substitute for quarantine.> What can and cannot be dipped, i.e.. corals, fish, invertebrates? <No inverts or corals should ever be FW dipped.  Some corals can be FW dipped as an extreme last ditch measure.  Some folks advocate full strength sea water with added iodine as a dip for corals, but there is no clear benefit to this.> How long do you dip for, I know to watch the fish for signs of stress but are we talking seconds/minutes/hours/days? <Any FW dip less than five minutes is useless.  Ten minutes should be considered a practical minimum, and fifteen more ideal.  Most healthy fish should tolerate longer.  Scaleless (blennies, eels) fish will only tolerate shorter dips.  Hyposaline quarantine (s.g. 1.014) can be tolerated for weeks with most fish.  Hope this helps.  Adam>

Methylene for Mandarin Dear Crew, First off, you guys rock. If you ever need any help editing your content or organizing your site, let me know. I do tech documentation for a living and have HTML skills.  <Bob may very well be interested, but keep in mind this is a volunteer site.> Now, to my question. I am - in the near-soonish but not today timeframe - getting a spotted mandarin. I have been preparing for this for some time. I have a 125 with 140 pounds of live rock. 50 pounds of the rock was seeded for 2 years prior to being put in the tank and the 125 is crawling with amphipods, copepods, and the like. The tank itself hasn't been set up perhaps as long as some might like (about 3 months), but I feel that the use of the seeded rock and sand made a big difference. There will be no aggressive fish in it; the stocking plan is clowns, cardinals, neon goby, Firefish, etc. <Sounds like a well thought out stocking plan>  The only current inhabitants are the clowns, who are doing fine after a month and growing like crazy. When the mandarin is put in, there will be the clowns, 2 cardinals, and a neon goby. So no real competition, except possibly the cardinals, but they are weenies. I have an offline 10 gallon tank propagating pods as food for the mandarin and anyone else who comes to brunch. I'm looking to get my fish from Dr. Mac, who has managed to get his to eat frozen food and customers of his back this up (and I've been pleased with my purchases from him).  My question relates to the process of QTing the mandarin. I have about 5-6 pounds of live rock that I have set aside for the mandarin to use in the 20gallon QT. He's going to be quarantined with a tank-bred royal Gramma.  OK. A lot of babble - now the question (really!) - Should I dip the mandarin pre-QT? I've read the FAQ and I know not to use a FW dip or to use copper on him. However, would a SW Methylene blue dip be OK? Or even advisable? Since the Gramma is coming tank-bred, I'm hopeful there won't be any disease issues there. In fact, the mandarin is the first fish I've run through my system(s) -ever- that hasn't been tank-bred.  <Angela, it is not a good idea to treat any fish unless it needs treatment. Just do the regular QT procedure. James (Salty Dog)> Wow. I just realized that! Thanks for your help <You're welcome> 

Methylene for Mandarin - A New Volunteer?  Not for the Usual Stuff <Bob may very well be interested, but keep in mind this is a volunteer site.>  Oh, I was well aware of that. I count WWM as the major reason for my success (albeit modest) in the hobby. Just wanted to offer my services back if there's something that needs to be done. <That is very thoughtful of you Angela> <Angela, it is not a good idea to treat any fish unless it needs treatment. Just do the regular QT procedure.> Okay. I know some folks do a preventative dip before they QT their fish. I haven't as a rule, but did know it was common. I'll put the mandarin and goby straight into the 20 and stuff 'em with pods.  <Good idea> Thanks again for all you guys do!  <You're welcome. James (Salty Dog)> 

- Methylene Blue FW Dips and Inverts - Dear WWM Crew, There is conflicting information on the Dip and Meth Blue FAQ pages regarding using Meth Blue FW Dips for inverts. Can you clear this up for me?  <I can try.> Fenner says "Yes to your suspicion re the warning label use of Methylene blue on invertebrates... this mild disinfectant is more important as a light shading agent, and oxygen carrying dye than anything... in the dip procedure... relatively very non toxic to both fishes and non-fishes at proscribed doses...." <I was not aware that Bob had said this, and he's out of town right now so I can't ask him to clarify. I've never used Methylene blue to dip anything other than fish - the bottle does state that it can impact your biological filter so I take that warning to mean the compound is harmful to invertebrates as well. That being said - "non-fishes" doesn't necessarily mean invertebrates.> J- says " do not use Methylene blue on ANY invertebrates, they will perish." <I did say that, yes.> My situation - I'm adding a clean up crew to my inherited fish/mushroom corals tank. My first batch is Turbos, emerald crabs and scarlet and blue-legged hermits. To dip or no?  <No.>  Freshwater dip only or Meth blue or something else?  <Neither... just acclimate very slowly and don't sweat it. And just FYI, the freshwater dip would kill these long before the Methylene blue did.>  Don't want to kill these things before I even get them into the QT. Thanks, Chris <Cheers, J -- > 

- Using Methylene Blue - Hello - I have read Bob's method of using Methylene blue and freshwater in a dip before you put the fish in a QT.  A Couple of questions for you on this.  <Ok.> 1) How long should you keep the fish in this alone?  <Ideally at least five minutes... longer if the fish will tolerate it.>  Also, if the fish does not seem to mind this dip should I acclimate him to the QT tank while keeping him in this solution?  <Don't bother with acclimation, just dip the fish and then place into the quarantine tank.> 2) What kinds of invertebrates will not tolerate this kind of dip?  <None.> 3) Would this work on corals?  <Not at all.> I just lost 8 fish in my main display to a parasite and do not want this to happen again. Will always QT everything before putting them in main display now. FYI - I am keeping my main display fish free for 6 weeks to make sure the parasite is gone. Will try my best to make sure no others will make there way in there.  <Sounds good.> Thanks for all the help guys.  Tom  <Cheers, J -- > 

- Using Methylene Blue, Follow-up - Thanks J. Just to Clarify. This will work on all invertebrates?  <Good grief... I just re-read your question and my answer, and I must apologize for not reading twice, or perhaps not having that second cup of coffee. I'll try to be more clear - do not use Methylene blue on ANY invertebrates, they will perish.> I also read around and it looks like it is not worth trying to dip the corals.  <There are other dips suitable for corals but I have no experience with that... would suggest you read Eric Borneman's Aquarium Corals and Anthony Calfo's Coral Propagation.>  Would you recommend QTing these for 3 weeks as well.  <I know Anthony would say absolutely... I personally have never quarantined corals... you'd have to have a very good and separate quarantine system for corals... very different requirements from fish quarantine. Would still need good light and excellent water quality.>  I have a light that would be good enough for LPS, but not strong enough for SPS. 32 watt 50/50 over a 10 gallon QT tank.  <And perhaps not enough water to insure stability... would be best to have a larger tank for this.> Maybe I am just being too cautious now, but I do not want to unintentionally kill any more critters.  <I can think of few that do, and I'm glad you wrote back... am mortified by my own poor response.>  Life is too short for these guys. Tom <Cheers, J -- > 

- Using Methylene Blue, More Follow-up - Thanks J.  <My pleasure. I'm glad I was able to clarify myself before you did something that I would have regretted.>  I have Bob and Anthony's book "Reef Invertebrates". Great book have read it front to cover and use it to look things up all the time. I will be getting Anthony's "Coral Propagation". <Sounds good. Cheers, J -- > 

Methylene Blue, molecular weight, availability I am writing in regards to the Methylene blue dip. None of my LFS have this, but I work in a lab and so I ordered some from Sigma, but all they have is Methylene blue hydrate, it is a blue powder with a molecular weight of 319.9 g/mol. Is this the same thing, I really need to use it, but I do not want to use the wrong thing. Thank you, Jessa <Mmm, I have Molecular weight : 373.90 Molecular formula : C16H18CLN3S.2H2O for this compound... But I would just buy a pre-made solution for your use here... at most any livestock fish store (LFS), or from an online company (e.g. marinedepot.com, CustomAquatic.com...) Many manufacturers make these (Kordon, Aquatronics, Aquarium Pharmaceuticals...) there is no real reason to make up your own stock solution. Bob Fenner>

Weights of hydration! Methylene Blue I have the same molecular formula minus the two H2O which would account for the different molec. weights (is yours re-hydrated?). <Not completely and this would account for the diff. MW> I really don't have a choice if I can make it up as none of the LFS here have it and I do not really have the time to order it and I really don't want to use malachite green and Formalin which is what they carry. But if they both read C16H18CIN3S they should be the same thing. You said to use 1g per 100ml right? Thank you again, Jessa <Yes... simple to make, use... a wide range of efficacy, low toxicity. Bob Fenner, who wishes he had a recent CRC manual about>

Re: Weights of hydration! Methylene Blue Redux Why didn't I think of that first (looking it up in the CRC, though mine is from 1970) it lists Methylene blue  MW 319.86 it lists the same molec. formula (minus the 2H2O) Jessa <Ah ha! Bob F, a not-so old previous H.S. Chemistry teacher...> So I guess that means I have the right stuff. <Bingo. I think so. Bob F>

Re: Toxicity of Malachite Green and Methylene Blue Other than staining fish and silicone, what effect will Malachite Green and/or Methylene Blue have on nitrifying bacteria, live rock, live sand, polyps, anemones, starfish, shrimp and fish in a marine tank? <Am out visiting in Hawai'i and away from my ref. works (Nelson Herwig and Edward Noga principally as authors, sources) but will make the general statements that Methylene Blue has low to very low toxicity either on nitrifying bacteria, micro- or macro-invertebrates... but that Malachite Green will at therapeutic dosage mal-affect all. Bob Fenner>

Methylene Blue, Ich Blues Thank you for all your help. I used the Methylene blue/FW dip for 10m yesterday on 3 fishes that have a few spots of ich on them. Should these spots come off during the dip or are they just there but dead (hopefully). Jessa <You are correct in that the appearance of the dots may not indicate actual parasite presence, but I would dip these fishes again... And, I do not encourage folks to treat ich/whitespot disease with dips or Methylene Blue per se... Depending on what species of fishes these are, I would utilize a malachite green solution or possibly a metal salt. Please see here re: http://www.wetwebmedia.com/FWSubWebIndex/fwich.htm Bob Fenner>

Methylene Blue Dip question Hello Bob! I have the concentrated Methylene Blue, G.P. powder.   Can you tell me how I can create a dip at 50ppm? Thanks! Pam <... knowing the initial concentration... you should be able to calculate how much water total volume to dilute an aliquot of stock... as in the formula C1/V1 = C2/V2 where C1 is your stock concentration, C2 is what you're looking for (50ppm) and V2 is the volume of final solution you'd like... solving for the dilution (V1)... Bob Fenner>

Methylene Blue Dear Steve Pro or Mr. Fenner, <Anthony Calfo in your service> What can Methylene blue treat?  <wide range of uses... effective at killing many bacteria and some fungus> White spot? <best when combined with another treatment like Freshwater dips on saltwater fish. FW will drop the ich and the Meth blue will disinfect the wounds from the parasites> Is it effective? <very... in fact, it really must be treated in a separate bath or quarantine tank... never in tank display (it can severely damage biological filters)> Does it kill invertebrate? <yes... very hostile to invertebrates and amphibians> What damage can it do if poured into main system? <horrifying> Do you recommend it? <can be very helpful in dips and QT treatments> Many Thanks! Liao I Ching <with kind regards, Anthony>

Methylene blue Hi there, I've tried to find the answer on your site but can't seem to find it. I use a freshwater, Methylene blue dip (3 drops per liter) on all new arrivals but would like to add it to my quarantine tank as a preventative (tried Cupramine but it got ugly, lost a royal Gramma).  I would like to know what dosage to use as a preventative rather than a dip. Thank you Stephen <Dose is "stock solution dependent", in other words, different makers have different concentrations of their product. Most commonly it is prepared at 3.7 mg./ml.... I don't encourage the continuous use of Methylene Blue (in freshwater or marine)... as this material has a negative effect on nitrifying microbes (your biological filter). However, if you wanted to still use it, it can be applied at the 3 drops per liter likely with little ill effect. Bob Fenner>

Methylene Blue Dear Bob, I have been reading your articles for some time now and really appreciate the advice you provide. <Gratifying to read> Got a quick question. You discuss Methylene blue and freshwater as an excellent dip for marine fish. I followed through and purchased Kordon Methylene Blue. They recommend 5 teaspoons per 3 gallons of water. Their product is 2.303% solution. <Yes, and a good stock solution> I followed these directions and the water was completely deep blue. So much so I could not see the fish. I had to feel around for him with the net. I only kept him in there for three minutes since I could not see how he was doing. Did I do this right? Did I panic needlessly? I know you believe this product to be very safe. Please share your thoughts. <Do realize how blue these solutions are at full strength, and no need to worry. This procedure, product is very safe. Hmm, perhaps I should add a cautionary note whenever discussing the use of Methylene Blue so folks will realize just how dark they'll be... And encourage the use of largish nets where maybe the organisms can be dipped/removed without leaving the net itself... or do as we generally do... use a "pickle bucket" and a large enough net to "swoop around" the edge assuring the catch...> Sincerely, Carlos Machin <Be chatting my friend in fish. Bob Fenner>

Methylene Blue and Inverts I just purchased a clownfish and a cleaner shrimp from my LFS.  I want to dip the fish with a fw/Methylene blue dip then an intermediate SW dip (to cleanse the chemicals) before finally placing him in the quarantine tank.   >>I'm a proponent of freshwater dips for fish.  The Methylene blue is something I don't normally use, but it won't hurt for a dip.  It can affect nitrifying bacteria if left to pickle, though. As for the cleaner shrimp, I'm just going to dip him in the intermediate dip to basically rinse off the LFS' water then place him in the quarantine.  I know that Methylene blue is not supposed to be used for inverts so will I have a problem with cross contamination (i.e. the nets I use and the common quarantine tank)?  I can only afford one quarantine setup.  I'm hoping the intermediate dip will rinse off most of the Methylene blue so as not to cause a problem with the shrimp. >>Just rinse the nets, and as long as you've changed out the water with the Meth. blue I see no problems.  It isn't quite as problematic for inverts as copper is, for instance.  You appear to be taking good care and showing fair caution. Also, I will rinse the nets thoroughly with tapwater between scooping.  Will this be enough to keep the shrimp safe?   >>Yes.  I think so. In addition, will the net used for scooping the fish up from the Methylene blue dip and the actual dip container be contaminated w/ Methylene blue forever (i.e. to the point where I can never use it to scoop inverts)?   >>No, a good rinse should suffice. Sorry for the barrage of questions, but here's a few more:  I'm using 0.75 ml of Methylene blue solution (store-bought, 5% Methylene blue) for the quarter-gallon dip...is that sufficient?  Thanks in advance.   >>Not having used it for pre-q/t dips, I couldn't be more specific, but it sounds as though you'll be golden.  Just be sure to watch the fish for signs of distress and don't worry about holding to any "hard and fast" rules for dipping.   Marina

Methylene Blue, Formalin effects dear  Bob! would you please let me know the answer of my following questions: 1- it is mentioned that "Methylene blue" that is a common chemical for disinfection of fish egg, also has another function ,so that increase the animal pole of the egg's this correct? <Yes, a "side-effect"> if is, why the development of animal region of egg is important? <To enhance development> 2- also, in some reference we read about the use of Formalin (for disinfecting the culture media) for example 12 or 24 hours before introducing the fish or rotifer in the culture). what is the reason? <To reduce the likelihood of microbial, protozoal competition, disease> does Formalin loss its effect after these times .doesn't it have any danger for cultured organisms after this time. <Indeed it does. Depending on many circumstances, BOD, temperature... there might well be sufficient residue to kill all. I would rinse the containers thoroughly before using. Bob Fenner> regards Reza

Singing The Methylene Blues? (Which Methylene Blue Is The Right One?)  Before I begin I want to thank all of you for the great things you do for the visitors of this site. I hope to emulate someday.  <So glad that you enjoy the site! Scott F. here today>  I have been searching for sources of Methylene blue. Not a very big deal, but which is the sort used for dips? I have come across Methylene blue thiocyanate, Methylene blue trihydrate, etc. Obviously, I don't want to throw some fish into the wrong stuff.  Thanks, Barry Jennings  <Well, Barry- that's a neat question- but, being a simple guy, I can offer a simple answer: I'd only use a brand of Methylene blue specifically packaged for aquarium use; many brands can be found on various e-tailers throughout the internet, or at your local fish store. With very few exceptions, when in doubt, I'd always pay a bit extra for the aquarium-specific product...Better safe than sorry. Hope this sets you on the right course! Regards, Scott F.>

- Using Methylene Blue - Hello - I have read Bob's method of using Methylene blue and freshwater in a dip before you put the fish in a QT.  A Couple of questions for you on this.  <Ok.> 1) How long should you keep the fish in this alone?  <Ideally at least five minutes... longer if the fish will tolerate it.>  Also, if the fish does not seem to mind this dip should I acclimate him to the QT tank while keeping him in this solution?  <Don't bother with acclimation, just dip the fish and then place into the quarantine tank.> 2) What kinds of invertebrates will not tolerate this kind of dip?  <None.> 3) Would this work on corals?  <Not at all.> I just lost 8 fish in my main display to a parasite and do not want this to happen again. Will always QT everything before putting them in main display now. FYI - I am keeping my main display fish free for 6 weeks to make sure the parasite is gone. Will try my best to make sure no others will make there way in there.  <Sounds good.> Thanks for all the help guys.  Tom  <Cheers, J -- > 

Methylene Blue in shipping Hi Bob, I notice the fish we brought in from ORA were shipped in what appears to be methyl blue. My understanding is you get a) antimicrobial effects, b) improved O2 transport, and c) sluggish fish. <Bingo. Now you're firing on all cylinders> Seems like something we ought to try for the fish from PI. Do you know the dosage appropriate for shipping? (I've seen mention in your dip article, but suspect that is stronger) <Yes again... difficult to gauge, state actual dosages... Methylene blue is VERY safe... almost not over-doseable... blue as blue is okay> Thanks again for the help. -Keith P.S Don't take my comment about fish pics wrong - I don't call 'em "Michael Mutants" for nothing :^) I did hear once also to never trust someone with 2 first names. >> Hmm, don't know if I'm following the above... But you can gladly call be Bob/Robert... and I won't take offense... just don't call me, as the saying goes, "late for dinner"... Bob Fenner

Angel With An Infection? I have a pair of Bellus Angelfish, I have had them a tad over a month now.  Both are doing great, except...My female has patches of white (not ich) on her side, they are getting a tad bigger, no other fish are affected.  Could this be bacterial in nature?  How do I treat her within the main tank, she can not be removed (to many corals and rock)?  Will the bacteria go away on it's own? <Hard to say. In the presence of excellent water conditions, anomalous growths like this will often spontaneously disappear without much intervention on the part of the aquarist. I'd maintain great environmental conditions, keep the fish well fed, and observe it carefully. Be prepared to intervene medically (in a separate tank) if required.> I have added another injector to my skimmer, my water is excellent, I do weekly water changes religiously....  Please help...I have enclosed a picture taken a week after I got them, as you can see all is fine.  At first it looked like little scrapes, now white patches. <Could simply be a localized infection of some sort brought about by a minor trauma. Do observe the fish carefully. If you need to treat the fish, something as simple as a long dip in Methylene blue might do the trick (of course, this would be administered in a separate container. Keep observing this beautiful fish and stay on top of things! Regards, Scott F.>

Become a Sponsor Features:
Daily FAQs FW Daily FAQs SW Pix of the Day FW Pix of the Day New On WWM
Helpful Links Hobbyist Forum Calendars Admin Index Cover Images
Featured Sponsors: