Treating Fish With Human Metronidazole   9/30/06
Dear Bob. I would appreciate your advice. My fish he has been off his food for 3 weeks and in the last week has stopped eating altogether. A once friendly fish, he is now withdrawn and hiding. Before he stopped eating he was passing stringy white pooh. He has not passed any pooh for 1 week since stopped eating. I would like to ask your advice on using Metronidazole 200mg tablets the type we take. I have read so much which is the correct way to treat my fish without harming the other healthy fish. Would Metronidazole be effective in the water if the fish is not eating as I understand tropical fish do not drink the water as marine do?. Would appreciate your advice my tank is 125 litres my other fish are rainbows, giant danio, 2 pearl catfish and a rosy barb. Thank you Tina  
< Use 500 mg of Metronidazole per 10 gallons of aquarium water. Treat every other day while doing a 50% water in-between treatments. After three treatments you should start to see some improvement. A hospital tank is best but it seems pretty harmless in a general community tank. Some aquarists add Nitrofurazone to the water too. This medication will harm your biological filtration.-Chuck>

Re: High Mortality Rate, FW, poss. Hexamita/Octomita  - 07/03/04
Thank you for responding so quickly.  The treatment we used contained was Parasite Clear Tank Buddies which includes the following ingredients:
Praziquantel; N-[[(N-Chlorophenyl) amino] carbon 1]-2,6-difluorobenzamide; Metronidazole; acriflavine.
<Correct>
Is Metronidazole different from Metronidazole/Flagyl?
<Mmm, no. This is the same compound... two different names>
Could part of our high death rate being caused by not changing the carbon filter enough?
<Not really likely... perhaps a small contributing factor>
We change it about every 2-3 months.  However, our water quality always seems to be good.
- Molly
<How to state this... There are many such qualities for which there are no tests, little practically known... re their effects alone, in synergism with other factors... Bob Fenner>

Boatloads of problems, trying to cope! Guppy disease/s, Neon Bloating, Imported fishes and Flagyl  - 05/22/2006
Hello,
<Hi there>
Wonderful site you have here.  Thank you for the resource.  I have combed it thoroughly over the last little while and have had some successful results with other problems, but now I am facing a few fish troubles I can't resolve and desperately need some help.
Unfortunately, this may be a big one as  I have two tanks; one 96 Litre and one 54 Litre tank.  Both are planted.  The relevant parameters for both tanks are:
96L:
pH 7.5
NitrItes: 0 ppm
NitrAtes: 12 ppm
KH: 6 dH
GH: 9 dH
Temp: 24 C
54L:
pH 7.5
NitrItes: 0.3 ppm
NitrAtes: 12 ppm
KH: 6 dH
GH 10 dH
temperature: 26 C
<No ammonia in either/both I take it>
I'll discuss the large tank first.  
In the 96L tank I keep guppies, platys, Corys and apple snails (Pomacea bridgesi).  I have noticed that the guppies have started flashing.  It is more than the "once per second" rule.  This has continued for about a week now.  I have not treated with malachite green (snails in the tank) nor have I added aquarium salt.  I have been observing the behaviour, as I mentioned, for about a week.  As of yet, I have seen no sign of ich, velvet or any visible "hangers-on" parasites.  
<Might be environmental...>
First question: I am wondering what the flashing could be about?  I think the water parameters are quite alright and I have no visible evidence of parasites.
<For what you list test wise and can see, yes>
  Consequently I am baffled.  Also, if needed, could I add aquarium salt to the tank even though it contains snails and Corys?  If so, at what concentration?
<Mmm, not much salt... Please read here: http://wetwebmedia.com/FWSubWebIndex/saltusefaqs.htm>
Second issue: I purchased 3 brilliant yellow guppies to attempt to "rescue" them as they were a little under the weather at the fish shop.
Guppy #1 swims in one position at the top of the tank and exhibits white stringy faeces.  Fins are not really clamped per-se, but maybe a little.  He will swim for hours in the same position at the top of the water, other than that, there is no visible sign of problems with him.  Abdomen does not look particularly bloated.  He will not take food.  Wondering if this is simple constipation or something more sinister in the works?
<Is possible there is a problem here... perhaps protozoal... that might call for a one-time treatment with Flagyl/Metronidazole...>
Guppy #2 has improved over the last day.  He has what looks like a tiny red blood blister on his tail.  There is also a split in his tailfin.  He is now swimming with the other guppies in the tank and eating a little bit.  He also had what looked like an abrasion on his head.  I treated him with Sera Baktopur for this (30 minute dip upon arrival and a couple of successive 30 min dips).  Should I be doing something further for this guy?
<Not at this juncture. More such exposure may be more harm than beneficial>
Guppy #3 I am the most concerned about.  He has what looks like blood under his scales near his head.  He hangs out on the bottom of the tank quite a lot - he actually "rests" on the bottom.  Occasionally he will swim up near the top of the surface and stay there for 20 min.s or so.  Will not take food.  In all cases, he looks like he is gasping, not super-heavy gasping, but I can tell this is what he is doing through comparison with other fish.  I think over the last 24 hours the red spot has decreased in size (hard to tell exactly), but he still maintains the laying on the bottom posture.  Wondering if this is hemorrhagic septicemia?  If so, what do you advise treatment with?  I am in Switzerland, so if you can suggest a Sera brand product that would be great (seems to be all they have here), otherwise I will need a chemical name.
<How to make this known... Poecilia raised in the orient (where the majority originate now-a-years, are often plagued with such complaints... Quarantine, some prophylactic measures are absolutely required... and should be S.O.P. by the trade/wholesaler-importers... but are rarely done... There are seasonal huge guppy die-offs on import, distribution... in the Spring, Fall...>
On to the 54 litre tank.  
In this tank, I keep a Betta, 11 neon tetras (the Betta does not bother or interact with them), 2 cherry barbs, two albino Corys, a small Pleco (was labeled "silure bleu" in the store)
<Unfamiliar with this>
and two freshwater shrimps.  The problem in this tank is with the tetras.  When I feed them flake (Tetra brand) their abdomen bloats up considerably.  Three tetras in particular develop swimming troubles.  They angle downwards about 50 degrees and swim towards the bottom.
<Do switch to non-dried food for a few weeks...>
They seem to "float up" and repeat this type of bobbing behaviour.  It is clear that the fish have buoyancy problems.
<A bit more than this...>
After about 4-5 hours the bloating goes down and they return to normal.  This has been going on for about 5 days now.  Feedings are done more than once per day and in very tiny quantities.  They may get some excess bloodworms that the Betta does not consume, but I am careful about over-feeding.  NitrItes are elevated in this tank because initially I thought the tetras may have had an internal infection and treated the tank with Baktopur.
<See below>
I suspect it impacted the biological filter resulting in the nitrIte rise.  
<You are correct here>
I am doing water changes to keep these down and have added a product called "Nitrivec".  The best I can seem to do at this point (70-75% water change) is to get them to 0.3 ppm.
My question would thus be: what is going on with the tetras?  
Could this be a food issue or is it an internal anatomy problem?
<Both>
They were having this problem before the elevated nitrIte levels, so it is seemingly unrelated to that.
A whole host of problems, I know.  If you can shed some light on even a few of them I would be most grateful!
Regards to the entire WWM crew and thanks in advance for any help!
<Am wanting to relate sufficient information to assist you here in aiding your livestock. Both systems do likely have a protozoal complaint. I would read here: http://wetwebmedia.com/metranidazole.htm
and utilize this powerful compound in these fishes foods... and be very careful re quarantining all new livestock to avoid re-infestation. Bob Fenner>

Re: Boatloads of problems, trying to cope! - FOLLOW UP  - 05/22/2006
Hi Mr. Fenner -
<John>
A million thank-you's for your reply!  I will give you a bit of updated information on the two tanks.
<Okay>
First of all, I cannot test for ammonia.  There are no such test kits available in Switzerland.  I suspect this is environmental regulation.
<I believe you are right... one of the reagents does pose substantial risk>
To use an unrelated example, any type of solution that decreases pH requires the name and address of the purchaser to be entered in a registry.
<Mmm... including vinegar?... I must have my balsamic to cook with, salads...>
The only test-kits available are for nitrItes, nitrAtes, pH, O2, CO2, KH and GH.
They do have a product called "Toxivec" on the market which will reduce nitrIte and ammonia, but it inhibits conversion of nitrItes to nitrAte.
This, in my opinion, is not the route to go as I suspect it will prevent the successful establishment of nitrIte converting bacteria.
Anyways, on to the tanks:
96 L:
I am still observing the flashing and there is still no outward sign of any parasitic infestation. I will continue to keep an eye on this.  Are flukes
always observable?
<Not with the "naked eye" generally. Requires a microscope to be sure>
Guppy #1 has continued to improve.  He is eating and schooling with the rest of the guppies.  I am beginning to be much less concerned about this one.
Have observed normal bowel movement.
Guppy #2 has worsened considerably.  The red spot on his tail has turned into a raging bacterial infection and about 1.5mm of his tail (all along the edge) has been consumed in the last 24 hours.  I am now treating him at full dose with a solution containing acriflavine, methylene blue and phenylglycol.  This seems to have halted the progress of the infection and the bright red areas are getting darker and, in some small areas, white.  I suspect I am getting a handle on this problem, however,  I am still concerned about this fish.  He has taken to hiding in the plants, but is quite active if disturbed by other fish.  Fins are, surprisingly, not clamped.  I am encouraged by the slowing of the infection, but not much else at the moment.  Hesitant to treat with Flagyl at this point as his situation seems delicate.
<Understood>
Guppy #3 has improved a little bit too.  The hemorrhaging on his head (picture is from yesterday, today this spot is hardly visible) has cleared up dramatically in the last 12 hours. He is no longer resting on the bottom, but is swimming rather consistently.  He is not "full of energy" so to speak, but at least he is moving about.  He may have attempted to eat, but was difficult to definitively see this.  I am less concerned about him at the moment although I do observe him to be somewhat lethargic.  I have attached a picture from yesterday.
The 54 litre tank:
Thank you for your advice regarding the tetras.  I will see if Flagyl is available here and definitely give this a try.  If this is protozoal, is there a possibility of transmission to the Betta?
<Yes... the likely causative agent (Octomita) is capable of infesting most all fishes... some groups more readily than others>
Speaking of which, he only seems to take blood worms.  I have tried  him on daphnia with little success - he will mouth it and the spit it out.  He will take some flake food (not much) and will also consume some Spirulina pellets.  I am worried that he, being a carnivore, is not getting a sufficient variety of protein by eating only the bloodworms.  Am I justified in thinking this, or can he live on the bloodworms and flake?  
<Can>
Have read the Betta FAQ, but I am concerned regarding variety in his diet.
The small Pleco is an Ancistrus, but not a Bristlenose (saw this on the nameplate).  Max size (according to information in the store) is 7 - 8 cm.
He is spotted white with a white tip on his tail.  Looks like a miniature version of a common Pleco.  I have attached some pictures.
Thank you so much for your help.  The information regarding the livestock practices was much appreciated.  I believe it is important for the
consumer/hobbyist to be aware of this.
My best to the crew!
<Thank you my friend. Life to you. Bob Fenner>

Re: Boatloads of problems, trying to cope! - FLAGYL APPLICATION IN PRACTICE  - 05/22/2006
Hello Bob,
<John>
Thank you so much for all your help, it means a lot to me and I know you invest loads of time and energy in your website.  I admire and respect you greatly.  Please rest-assured that your service is much appreciated.
<Very glad to share>
State of the tanks:
Unfortunately, I lost two of the yellow guppies today but I expected some
losses given the condition of the fish upon receipt.
<I as well on reading your excellent descriptions>
Both had very nasty external bacterial infections; red sores and tail damage.  However, I think the one remaining yellow guppy will survive.  He has a split in his tail and a small red spot, but he is active and taking food!  He continues to school with the group and my outlook for him is positive at the moment.  I suppose a 33% survival rate is better than 0%.
Anyways, I have a question about the Flagyl.  I cannot get a commercial preparation, but I was able to procure some 250mg solid tablets.  I have pulverized one into a fine, fine powder and mixed it with 25 mL of water to make a 1% (by mass) solution (is this okay?
<Yes... is very water soluble>
Hopefully you won't tell me to do this by volume.).  I know there are water solubility issues with Flagyl, but like I said, commercial solutions aren't available here in Switzerland.
Call it "front-line" medicine if you will...I trust that this will be sufficient for treatment.
After having prepared the Flagyl solution, I have soaked some food in the liquid for about 2 hours now (in the refrigerator).  I am basically ready to give this to the fish, but would like clarification on something.  I am feeding several fish here.  I suspect some fish will get more of the treated food than others so there is a chance that some fish may not receive either a substantial dose or any food at all.  Thus, I suspect I will be feeding the medicated food both today and tomorrow.  Is this a suitable spacing or should I feed today and then, say, Friday?
<Either one/way should be fine here>
I was thinking to remove any fish that didn't receive food and feeding them separately but, as they all look the same, this may be impossible so let's go on the premise that they will all be fed simultaneously.  Given the dangers of accumulated dosage, and the chances of some fish not getting much food, are two applications sufficient?
<Yes>
Also, are these suspected protozoa water-borne?
<For part of their life-cycle, likely so>
That is, should I also be treating the water to prevent re-infestation?  If so, with what?
<Mmm, this one time use should "do it">
Final question regarding Flagyl: there are freshwater shrimp in the tank and they will undoubtedly eat some of the food.  Are there any issues to be aware of here?
<None that I'm aware of, no>
Also, guppies are flashing furiously today.  I am truly suspecting parasites of some sort.  As there is no sign of ich, I am leaning towards body flukes.
I have a solution containing:
210 mg of Acriflavine
112.5 mg cupric sulphate
15 mg cupric chloride
<Copper compounds will kill your shrimp assuredly>
that may be helpful here - certainly better than malachite green.  Will this be detrimental to the apple snails (Pomacea bridgesi)?
<Yes>
I will remove for the duration of treatment, if so.
<And utilize carbon filtration ahead of their re-introduction>
Best regards to you all.  I assign a finite value to the service you provide.
<Sorry for your travails here... Bob Fenner>

Re: Boatloads of problems, trying to cope! - FLAGYL APPLICATION IN PRACTICE  - 05/23/2006
Hi Bob,
<John>
Thanks for the fast, fast reply...
<Welcome>
At the end of the previous message, I meant to say: "I CANNOT assign a finite value to the service you provide."  Sorry if that came out the wrong way!  I certainly did not mean it that way...your help is absolutely amazing.
<Mmm, thank you>
Thanks again.  No problem about all the travails.  Live and learn as they say.  I've been through a lot worse in life, so some aquarium tank problems seem minor at this point.
<Ahhh>
Also:  Oddly enough, they don't require you to sign for balsamic vinegar...
Best to you.
<And you! BobF>

Re: more on Cichlid tank and Flagyl   4/16/06
The current sizes of the present cichlids are as follows, Oscar 8  inches, Dempsey 5 inches,  Pleco and angelic catfishes are both  around 3 inches.  Can I add another cichlid to the 75 gallon  tank.  Thanks again
    Jim
  Second, the tank these fish came from was a 30 gallon, my Oscar got  hole in the head and lateral line disease before the switch. I have  been mixing Metronidazole with his food.
<... a very poor idea to "keep" mixing this protozoacide/administering it more than once, twice. Is toxic, will kill your fishes renal/kidney systems>
His  behavior and appetite is fine, the only problem is the holes and scars  on his head and body. My water conditions are fine. will the extra  space in the 75 gallon solve this problem with my Oscar?
  <Perhaps... see WWM re nutrition and HLLE... this is the root cure, along with improved water quality en toto>
  Finally, I live close to the ocean and fish very often, can I feed my  fish live bait fish from the sea such as killies and spearing?
  <Yes>
  Thank you in advance for your patience and help.
  Jim
<Keep reading... the materials archived on WWM re Oscars, other cichlids... http://wetwebmedia.com/FWSubWebIndex/fwlvstkind2.htm
Bob Fenner>

Treat Tank Bred Clown & Mandarin with Metronidazole?   3/4/06
We have had a pair of Mandarins in QT with plenty of live rock and copepods for 3 weeks.  They seem to be doing great (getting a little fatter every day).  We purchased 2 baby tank raised clowns and a Fromia last week.     
  We had planned to put the clowns in QT with the Mandarins for 4 weeks and observe them (thinking they were tank raised from a reputable source so they should not have parasites).
<Likely not from the source... but easily pick up in systems at stores... where water, gear are mixed...>
  After acclimating, we realized that one of the clowns pectoral fins were half gone (I'm guessing ammonia in holding or shipping?).
<Mmm, more likely a genetic anomaly... like... Nemo... But possibly>
So, we changed plans and put the clowns and Fromia in a new QT (cycled - aged filter).
   The clown with bad fins is coming around nicely.  We have really babied both of them.  We've fed mostly vitamin enriched fresh brine because the one with damaged fins still has a little trouble swimming and opens/closes his mouth constantly.  Both have grown significantly over the week.  The damaged clown's symptoms (other than the pecs) are opening and closing of the mouth and sometimes stringy white feces. His fins are improving slowly, as is his swimming.  All of my reading suggests that he may have internal parasites even though he was tank raised.  I believe we need to treat with Metronidazole in the food (brine for now in his case).
   <Worth a try... I would not do this in the presence of the Fromia star>
  My dilemma, we have a Fromia in the tank with them and also may have contaminated the Mandarin QT in the hours before we setup the 2nd QT (water transfer - the fish were not released into the tank).  Will Metronidazole hurt the Fromia?
<Too likely yes>
Would it work to setup a third QT and move the clowns back and forth for feeding/treatment (don't have enough cycled filter media to move them full time yet).
<Yes, this is the best idea>
Should we treat the Mandarins before moving to the display even though they show no signs (I think they would have to be moved because there are inverts in that tank as well)?
   <I would not>
  Sorry for all the questions.  Trying hard not to contaminate the main reef and/or hurt anything!   Thanks in advance!
   <Understood, and no worries>
  PS  The Mandarins seem to LOVE fresh brine, so getting medicine in them should not be too hard (but some Metronidazole would still be in the water - and the inverts would of course eat the brine too).
<I would not expose invertebrates you wish to keep to this anti-protozoal. Bob Fenner>

Treating a Non-Sick Oscar   2/2/06
Thank you so much for you quick response.  Shortly after I sent the first inquiry the poor Oscar went flying around the cage uncontrollably as if shot
out of a gun and is now dead.  My follow up question is, do I need to be concerned with the other Oscar it shared the quarantine tank with? (They
also shared a tank at the store).  I certainly do not want the remaining Oscar to meet the demise of the first.  Would you recommend using the
Metronidazole as a preventative even though the remaining Oscar looks just fine? Thanks again for all the help, Aaron
< Continue the observation in the quarantine tank. If no problems are seen in a couple of weeks then he should be OK. I really don't recommend the Metronidazole as a preventative unless you actually see a disease.-Chuck>

Metronidazole Dosage  9/2/05
Dear Mr. Bob Fenner,
<Actually, Sabrina here this evening.>
I'm writing from Portugal, and I want to ask you what is the ideal dosage to apply to a 3 years old goldfish. It is suffering from swimbladder disease, and my vet told me to use Flagyl (liquid solution, not a tablet) in order to clean it from any protozoals that might be causing an internal infection.
<What brought him to the conclusion there were protozoans involved?  The most common buoyancy issue in goldfish is related to nutritional problems....  this often happens to goldfish that are fed strictly on flake or pellet foods.>
He told me to dissolve it into the water (1 ml/litre)
<Is it in a solution?  The highest dosage that is usually recommended when using Metronidazole is 6mg/litre.>
and to partially change it (80%) after 48 hours. The water to replace should also have Flagyl. In the total, I should have changed 3x times the water, resulting in a 48 x 3 hours treatment. I did it, and surprisingly, after 12 hours, my fish was relying at the bottom of the aqua (he floats upside down all the time, and can't go down easily). However, he was still upside down, and on opposite, he had now difficulty in going to the surface of the water!
<All sounds okay, aside from the goldfish's reaction....  and I'm still not convinced that it's a protozoan issue.>
Another problem was, that the water became very dirty, before the first 24 hours were completed, and I noticed that he wasn't feeling very well. I called the vet and he told me to put him in clean water for a while, continuing the treatment as soon as possible.
<You need to test the water for ammonia, nitrite, and nitrate, and maintain ammonia and nitrite at ZERO, and nitrate less than 20ppm.  Anything more than these levels would be toxic to the goldfish.>
I did so, and again, at the 2º time, I had to put him again in clean water (it was 4 days, and he was lying at the bottom of the aqua, upside down, and with difficulty to go to the surface...). I did another break, and when I was giving him the third dosage, he started to float again on the surface like a balloon! We were starting to have hope that he was going to heal, but suddenly, everything went wrong! According to my vet, he was getting better, and it should be just a question of time, to him floats normally again...he couldn't understand what happened and was afraid that my fish was allergic to Flagyl...anyway he told me to have another try after a couple of weeks, and see how this time the things work out... That's way I'm trying to find information about Flagyl usage and doses...I'm not sure if my vet recommended the right dose...his size is about 15 cm (head to tail), and he eats still very well, after + - 2 months floating like a balloon on the surface of the water. I have already tried several methods to cure swimbladder disease: peas, Epson salt, vicinus oil, Baktapur, increase water temperature, and so on... If you can help me, please do it!
<I think it is possible that this is purely a nutritional issue....  Please consider offering this fish a diet of strictly vegetable material (shelled peas, aquarium plants like anacharis/Egeria/elodea, blanched spinach....  and do not offer flake or pellet foods.  Just some things to think about.  Most importantly, be vigilant with water quality - and be testing for ammonia, nitrite, and nitrate!>
Thanks and regards.
Elizabeth Simão Carvalho
<Wishing you and your goldfish well,  -Sabrina>

Getting Meds for Sick Fish 8/4/05
Thank you so much for the info. Can you possibly tell me where I can acquire
some of the Metronidazole?
<DrsFosterSmith.com>  I called the local pet store, and they did not
have anything that had that ingredient in it. He is still alive, but not
doing well.  And can you tell me why one got this infection, and the other
two did not? Karen
< Usually stress. Being the smallest fish and being pushed around by the others or even too much food.-Chuck>

Metronidazole Harmful to Filter Bed?
Just a quick question.
You suggested treating my Firemouth for internal bacteria. infection with Metronidazole. Is Metronidazole harmful for the bacterial colonies in the filter? Thanks, Spyros < Metronidazole is suppose to be effective against anaerobic bacteria. It shouldn't but I would be on the safe side and check for ammonia after treatment. If the filter bed has been affected then I would add some Bio-Spira to the water to get it up and going again.-Chuck>

Finding Medications
Thanks very much again for your advice. While reading about Metronidazole/Flagyl, it can only be administered through food. What if the fish isn't eating? And is there a brand name associated with Metronidazole/Flagyl that I can find in a pet shop? Victoria Barba
< I still apply it to the water as per the directions on the package. Medicated foods are better if the fish are eating but unfortunately most of the time the infected ones are not eating. I am not aware of a brand name for Metronidazole.-Chuck>

Metronidazole in the U.K.
Hi Chuck, Thanks for getting back to me, you cannot buy these meds over the counter
here, however after telling my vet the name of the medication he sold me
some tablets of the same name. I had to crush and dissolve in water and put
in the tank. He has only had 3 hours so far, but if you get anyone else in
the UK - tell them to ask their local vet ! thanks again.
How long should I leave the Metronidazole in the water before doing a change
?
< Twenty four hours.-Chuck>Trevor in UK.