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FAQs on Characoids/Tetras & Relatives Disease Treatment

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Beware of metal and formalin containing medications. Toxic

Minor Serpae Tetra fin rot?     11/2/14
Greetings. I have a 55-gallon aquarium that we set up 2 years ago & has been stable and disease-free. Water parameters are: ammonia = 0, nitrite = 0, nitrate = 30, phosphorous = 0. I do a water change every week. We have live plants (water sprite wisteria). The inhabitants are 2 Bristlenose Plecos, 8 black-skirt tetras, 8 white-skirt tetras, 11 minor Serpae tetras, and about 6 apple snails. The Serpae tetras were introduced about 2 weeks ago and my quarantine tank currently is housing some baby Gold Gouramis, so
I chose not to quarantine them. I know I should have, but I have never had any problem with the tetras from this source. A bad decision on my part, but anyway, may I explain the problem to you...?
<Fire away.>
Oddly enough, the other fish in the tank seem to be still healthy and unaffected by this disease bothering the serape tetras. It is the strangest thing I have ever seen. The first sign is a very pale area where the dorsal
fin meets their body. It's very clearly delineated and easy to see against their red-orange background. Soon after that, the dorsal fin degenerates and the fish seems to die within a day or two after they reach that stage.
They don't seem swollen and neither do they show any other signs of illness. I have never seen fin rot behave like this or fin rot that just affects one species of tetra. Today, I got some API Triple Sulfa and am
planning on giving them the entire course of treatment as directed by the manufacturer. Do you think that I am on the right track here? Please advise and thank you so much for your time and any comments you may have for me.
<Serpae Tetras are notorious fin-nippers, so one explanation is that they're fighting within the group (which they do, especially when feeding) and damaging one another. When feeding they have a feeding frenzy
behaviour, but will also bully weaker specimens, even killing them. Usually they attack other fish too, but the Black/White Skirt Tetras (both Gymnocorymbus ternetzi) are pretty pushy, fast-moving little fish
themselves, and may be holding their own just fine. Gouramis, though, are easy targets so I wouldn't mix them. This said, it is rare for Finrot to kill fish within a couple days. Adding more Serpae tetras might help, by
spreading out any aggression, but before doing that you'd want to observe the Serpae Tetras and see if they're chasing or nipping each other. If they are fighting, adding a few more could be a good move. Alternatively, you might simply have a "bad batch" of Serpae Tetras, in which case medicating for Finrot might stabilise things, giving you time to see if they can be saved. If the fish get better, then no harm done. If they eventually all die, I'd recommend not buying Serpae Tetras again. Although cheap and usually extremely hardy, they aren't well behaved fish, and there are better alternatives such as Red Phantom Tetras out there.>
<Cheers, Neale.>
Re: Minor Serpae Tetra fin rot?    11/15/14

Greetings. Well, I treated the entire aquarium with API Triple Sulfa for four days and then observed the aquarium for several days and the mysterious problem of the bacterial infection with the Serpae Tetras seems to have been eradicated. All the fish look very healthy.
I have been watching them closely for fin nipping and have only seen a limited amount of chasing amongst the Serpaes and a few isolated incidents of them bothering the black & white skirt tetras who, as you previously
stated, can give it back to them even better than the Serpaes can dish it out.
<Often the case. Both species are "fin nippers" but Serpae Tetras tend to be more persistent and vicious, whereas Black Widows generally behave themselves if there's enough of them.>
I haven't seen them bothering the gold gouramis, who can be rather pugnacious also if they choose to do so.
<Males, yes; females less so, if at all. Also, as they age, they slow down a lot, making them easier targets, so do keep an eye out for them.>
I will watch the gouramis closely and move them to another aquarium if necessary. I will keep watching the Serpaes for aggression. I have not found anyone yet who has any idea exactly what this strange infection was,
but the guy at PetSmart said that the others that came in in that particular group had to be treated with antibiotics as well. Anyway, just to let you know what the outcome was with this incident. Thanks for the heads-up on Serpae aggression. I did notice that they are on nippy fish.net where they seem to be known as the culprit in many a fin-nipping incident.
<Indeed. Excellent fish in terms of colour, size, and usually hardiness.
They were extremely common fish in the aquarium hobby during its earlier phase. But nowadays are not as popular. Unfortunately some retailers give them alternate names, making it easy to buy them by mistake. Red Minor Tetra, Jewel Tetra, Hyphessobrycon eques, Hyphessobrycon calistus and Hyphessobrycon serpae are some of the names you'll see.>
Thanks again for your advice.
<Welcome. Neale.>

Treatment options for fungus in Jellybean Tetra (wild caught)    7/22/12
Hello again, crew!
You may remember me writing in a short time ago seeing advice on how to care for wild-caught Jellybean Tetra (Ladigesia roloffi).
I've had them (they're lovely) since Friday the 13th (O.o), and thus far things have been going well - I thought - unfortunately, this morning I noticed a cottony growth by the gill of one of them. I didn't want to stress them further, but felt it was important to show you what I see, so I'm attaching 3 images of the same fish, in the hopes that it will help you help me!
(link to photo:
This is the only obviously affected tetra at this time, though one of the others *may* have it on his top fin (which appears to have been damaged or nipped)
These two are among the smallest in a shoal of 20 - only about 1/2 inch long, if that.
Here is more info on the tank:
This is a 20g long QT tank that I set up just for them. There are more floaters now than there was when this image was taken (the day before they arrived). Most of the plants are real, except for the 'bamboo' floating - I didn't have enough floaters to provide adequate coverage, so I added some plastic ones in the hopes of easing any stress on the fish. Everything in this tank except the wood and plastic was taken from my original QT/plant grow-out tank, which was only a 10g. I didn't want to risk any fluctuation in the parameters, so moved everything over, including the substrate, plants, and filter. Also put in a 20g filter that has been on another tank for quite some time to ensure as stable of an environment for them, considering the new set up.
Ph 7.4 (a little bit high for Jellybeans)
<Yes; I'd keep under 7.0; do you have some water of lower pH to blend in? Peat or its extract to add?>

KH 2gtts
GH 6gtts
Nh4 - 0
No2 - 0
No3 - 5
Po43 - 0
Temp: 78-79 (also on the high side)
I've been trying to keep the temp low - I've read that 77 is their optimum temperature, with 79 being the max. I can't keep the tank under 78-79ish - it's just where my room temperature gets the water. I've been testing the water daily, and have seen no fluctuation in parameters since adding these fish. They are under a 10g hood lamp, which I've slowly been increasing in duration to reach 8 hours, with the intent of slowly switching to the standard size hood lamp for this tank.
<Leave this off by day, on at night... to discount it as a heat source>
The idea is to slowly get them used to conditions in my 29g community, which is where I hope they'll go eventually.
I've been doing a small water change and siphon the sand every 2-3 days.
I'm afraid to let them go a week because of the waste created by feeding them, as they won't touch food if it lands on the substrate,
<Floating small pellets, and/or flake... a few times daily>
and it's been a learning period for all of us. I've been feeding them lightly every day (I think - it's hard to tell because they're so small and so MANY of them - I'm new at this!), and have been skipping every 3rd day.
At first, they stayed on the opposite side of the tank as I siphoned (very gently and slowly, so as not to disturb them), but now they seem to have gotten used to it, and confuse it with the syringe that I feed them with and TRY to get to the siphon - so I kind of don't think I'm stressing them out with water changes, though I could be wrong.
<Better this than pollution>
I've actually never dealt with any type of fungus (if that's even what this is) in my tank(s) before, and am especially leery as they're very small and wild-caught. I sincerely appreciate any information and insight you can offer me in order to get my tank healthy again, and my little Jellybeans safely through this!
Let me know if there is any other information that might help. . . thank you very much!
<Your water quality reads as otherwise excellent. I would not treat the system for this one fish, nor remove it to treat elsewhere. I too think this may be an opportunistic infection (bacterial but possibly fungal) w/ the one fish being physically traumatized; and will heal of its own accord w/ just good care, time going by. Bob Fenner>

Red Phantom Tetra can't open his mouth 12/18/10
Hi Crew,
I hope you can shed some light on this problem. Here's my set-up:
20 gallon tank
Ammonia 0, Nitrites 0, Nitrates 10
8 red phantom tetras, 1 Farlowella, 1 dwarf Gourami, 6 peppered Cory cats
live plants
temp 76
I've had this tetra in question for 2+ years. A bit of background that may or may not be relevant - he was either born with a curved spine, or he was injured on the trip to the LFS. From day one you could see his spine was curved. However, he has been fine for 2+ years, could swim just fine though perhaps he is tipped upward a little bit when he is stationary but otherwise has been normal.
<I see>
I noticed a few days ago he seemed to be moving a lot more, constantly swimming but not as he normally would. He is tipped upright more than usual and never rests even for a second. He also seems to be a bit stiff in part of his body but I can't quite put my finger on where (possibly his upper body but hard to tell).
When I fed the fish he seemed to react and swim around the food, but made no attempt to eat. I knew something else was off about him and couldn't put my finger on it until tonight...he isn't opening his mouth at all! Not to eat, or as fish normally open and close their mouths. It is like his mouth is fused shut.
<Mmm, happens...>
I put a magnifying glass up to him and don't see any growth or obstruction but he is so quick to move it is hard to tell.
Should I put him in a separate tank (and possibly treat with something?).
Any idea what this is, and are my other tetras at risk?
<I'd leave this fish where it is. Not "catching"... either developmental or a trauma (bump into something hard)... Will cure of its own or this fish will perish in time from a lack of nutrition>
Thanks so much for your time!
<Welcome. Bob Fenner>

Neon tetras--strange growths   4/24/07 Thanks for an excellent resource! I did peruse the FAQs before sending, and cropped and reduced the attached photos. <Good> In general, my 20 g long tank is fine. It's a planted tank (java ferns, dwarf sag, Christmas moss, Monoselium tenerum) with 1 SAE, a number of "wild cherry" shrimp (Neocaridina denticula sinensis) and 12 neon tetras. I've had some of the Neons for  a couple of years; I added 6 a few months ago. The tank in general is doing well. The younger Neons spawn regularly ( I just saw them doing it a few minutes ago.) I was about to test the water for pH before I sent this e-mail, but found I was out of reagent. It usually tests around neutral in the tank, out of the tap it's usually 8.0, but I have the tank on DIY CO2. <Very good> The temperature is usually at about 73 F, but they've been goofing with the A/C in my office building, so now its a bit cool (70 F.)  Anyway, some of the older Neons have this strange growth as you can see in the picture. It started months ago on one of them, but didn't/doesn't grow very quickly at all, and at first did not seem to affect other fish in the tank, but as you can see, that has recently changed. It often seems to start as a small growth on the mouth, and then shows up elsewhere. There are about 6-7 Neons in the tank that are unaffected, and about the same number that are, to varying degrees. I have a tank at home that stays in the low 80s (we live in Hawaii, no A/C at home) <Am out on the Big Island currently... mauka of Kona... at about 1,400 feet elevation... as many folks do here for moderation of seasonal temp.> with white clouds in it. I was wondering...would it be a good idea to swap tanks? <Mmm, yes> I know the Neons like it warmer, and the white clouds like it cooler... but would it be better to put a heater in this tank, rather than risk infecting the white clouds with whatever this growth is? <I don't think this growth, condition is "catching" from the Neons to Tan's fish...> Once again, thanks for an excellent resource! I appreciate your help tremendously!! Rus Wilson <Thank you for writing, sharing... I would switch out these two fish groups... I strongly suspect that the better part of the older Neon condition is largely age-influenced... They only live a few years... And would not attempt actual treatment/s other than to move them to the warmer setting. Bob Fenner>

Fish can't swim, FW mysterious paralysis in Tetras  -- 03/09/07 Hello, I am having an issue with the fish in one of my tanks everything water wise is fine (ammonia 0, nitrite 0, and nitrate 10) and it is a heavily planted tank. but a couple of the fish have died and a couple that are alive seem to have rigor mortis in their tails and can barely swim( they are couple of Rio von tetras and green flame tetra). CJ <Yikes... very strange... and no way to diagnose w/o much more information... I would do the S.O.P. in such anomalous cases, a good-sized water change (perhaps half) and addition of a chemical filtrant (likely activated carbon, or a product with a preponderance of such). Now! Bob Fenner>

Sick Phantom - 10/21/2006 Hello, <Hi, Camille.  First, I apologize for the delay of this reply.  It was not easily accessible by our mail system, unfortunately.> I have a sick Black Phantom tetra and I'm not sure how to help her.  She has a rapid respiration rate, and is having difficulty keeping herself upright; she tends to flop over on to her side, or her head points down towards the gravel and her tail points up towards the water surface. She's still eating, and I don't see other visible signs of disease (no discolorations, bumps, fungus, parasites, ragged fins, etc'¦).  She displayed similar symptoms a few months ago and I was not sure what to do for her, so I moved her to a quarantine tank with a little aquarium salt added, <This was an excellent move - though I would have used Epsom salt (Magnesium Sulfate) instead or in addition to the aquarium salt.> included a little bit of Aquari-sol (although I admittedly had no idea if this was the best idea or not'¦), <I would not have recommended this.> and fed her sparingly for a week.  Her condition improved greatly and I put her back in the main tank.   <Great!> A few weeks ago, I noticed she was starting to list to the side a bit again.  Her condition has gradually worsened, and I now have her back in the quarantine tank.  I have not started any kind of treatment yet, and would surely welcome some good, expert advice!   <I'd add Epsom salt (Magnesium Sulfate) at a rate of 1-2 tablespoons per ten gallons.  Aquarium salt certainly won't hurt, and may help.  I'd recommend strongly that you look very closely for any other symptoms - gray/filmy skin, any other abnormalities....  And perhaps also try giving her some foods of high roughage content - shelled peas or adult brine shrimp, perhaps.  These along with the Epsom salt will help to pass any gut blockage that may be affecting her swimming.  Withhold all other foods for a time.> My main tank is 55 gallons, planted with low-light plants (no CO2 added).  The tank has been set up for about one year.  Water conditions have been stable for a long time: pH 7.3 Nitrate 20 Ammonia 0 Nitrite 0 Temp 80 I do a 10 to 15% water change every one to two weeks.  I use AquaSafe to remove Chlorine/Chloramines.  I add Seachem's Flourish once a week and Excel 2 or 3 times weekly for the plants.   <Sounds great, though you may want to do larger water changes; the Nitrate's just at the edge of "okay".> Tank inhabitants: 4 Black Phantom tetras (2 males, 2 females) 5 Pristella tetras 6 Neon tetras 6 Panda Corys 3 Otocinclus All other fish seem to be fine.  What course of action would you recommend I follow to help my tetra?   <Just as above.> Any advice or suggestions will be greatly appreciated!  Thank you for your time.  Best regards,  Camille <All the best to you,  -Sabrina>

Is my Congo tetra carrying eggs?   7/6/06 Hello WWM Crew, <Jim> Simple a quick question, and yes I have searched around but I think it's just too simple and I am too cautious.  Judging from the attached photo, is my Congo tetra prego?  If not, what could it be?  It is acting perfectly normal and holding up its part of the 6 member school. Thanks in advance for your help. Best regards, Jim <If carrying eggs, not many... Looks more like an infection from the pinkish coloring in the vent area. At this juncture I would just keep observing... Bob Fenner>

Re: Is my Congo tetra carrying eggs?  7/9/06 Hi Everyone, <Jim> An update.  The lump on my Congo tetra, described below, has definitely not gotten any smaller and continues to be red.  Could the fish's vent be plugged up? <Mmm, possibly, yes> Can anything be done?  It continues to act normally, swimming with the rest of 'em and eating, etc. Thanks again, Jim <Mmm, well, there are "laxatives" in the way of foods... like the feeding of brine shrimp (Artemia) or Daphnia... that might help here. Even the careful addition of Epsom Salt (see WWM re: http://www.wetwebmedia.com/FWSubWebIndex/saltusefaqs.htm But I would take a "wait and see" approach here if this fish appears okay otherwise. It may well "self-heal" in your good care. Bob Fenner>

What are these things! FW Neons, Ich...    3/27/06 Dear WWM Crew, I have recently had all my neon tetras die. The first one to go (thing 1) had dropsy and was really sad because he had been a part of my aquarium for over a year. I went to the local aquarium to get two replacements to keep my second neon company. Within 2 days both of the new guys died. I tested my water and everything was fine. <Can't tell from here> The following day I bought another neon tetra and named in speckles (It had white dots sprinkled over its body and fins). <Perhaps if you named them after prophets...> This one soon died too, followed by my second neon tetra (thing 2). I noticed my other fish began having white dots as well. <Oops... likely not related... but Ich> (I have a flame tetra, two Gouramis, a Serpae tetra) Doing my research, I assumed Ich and began treating the tank with CopperSafe, as recommended by the aquarium store. <... I would NOT treat small characins/Tetras with Copper products... but half doses of Malachite Green, elevated temperature... posted on WWM> Paying closer attention to the tank, I can see many tiny white bugs moving on the glass and floating in the water that were not there before. <These also are very likely unrelated...> Can these white bugs be what is on my fish? Are they parasites hurting my fish? Thank you for your time, Jackie <The initial losses were probably due to simple differences in your store/sources water quality, acclimation and your system... the Ich was likely imported on some of the new fish... the bugs are likely living on the nutrients, food... You need to "step up" your maintenance, treat the Ich with something less toxic (likely clean the tank a bit first, or better, treat the fish elsewhere...), and not worry re the apparent "bugs". Please read here: http://wetwebmedia.com/FWSubWebIndex/fwich.htm and the linked files above. Bob Fenner>

Pop Eye on Tetra  2/18/06 I have a 100 gallon tank with 2 magnum filters going on. One of my tetras has a bubbled eye. What do I do? I need help. I have put him by himself in a small tank 10 gallon with half water which is 5 gallon water & did put that tablet fungus clear tank buddies. Do I have to add Epsom salt with it.?. Kindly respond. thanks. Godfrey < Treat the tank with the sick tetra with Metronidazole. The original tank may have elevated nitrate readings and so check the levels. They should be under 25 ppm although some fish like them lower.-Chuck>

My poor tetra... dropsy   1/17/06 Hello        I have a question regarding my tetra.  For the last 5 days or so my fish has been in the bottom corner of our 10 gal tank.  It can swim for a second then falls right back to the bottom of the tank.  I have two other tetras in the same tank and they are fine.  I don't know what a pregnant tetra looks like but this one is very fat and the scales are sticking out, <... Ascites... in pet-fishing called dropsy, or a Dropsical condition... aptly called "pinecone disease" in Japanese> the side looks red.   I have read about the different diseases and it seems like the fish might have a disease but the others ones don't.  I had my water tested when I took it into the pet shop and it is OK so I am stumped.  Would a fish not be able to swim if it had a disease and Say the fish is pregnant how long does it take to lay the eggs? <Depends on species... days to a few weeks> Should I take the fish out of the tank?  IF so what is the best way?  I am not to sure on fish stuff but I don't like to see fish suffer. <If you sense this fish should be sacrificed, placing it in a plastic bag with a little water and putting this in the freezer will painlessly euthanize it. Likely the "cause" of the dropsy here is not "catching"... Bob Fenner>

Silver Dollars with Fin Damage 8/21/05 I asked for help a while ago with my Silver Dollars looking extremely poorly. Ich causing large sores on their sides, and fin rot, you suggested a Furan based medicine and the continued use of Rid-Ich+. I'm now using Furazone-green (contains: Methylene Blue: 2.5mg, Nitrofurazone (Monofuracin): 122mg, and Furazolidone: 24.4 mg.) and I've doubled the dosage to one capsule twice a day as directed on the package as well as the Rid-Ich+. I've been treating one silver dollar in a ten gallon tank setup with no substrate under my 90 gallon for 10 days now. Figured this was a good location as this is a large, stressful fish and its inside a cabinet. I've noticed the major loss of Ich, and the slowly shrinking sores, but the fins, though no longer discolored, have not seemed to have grown whatsoever. I was wondering what other practices I could take to speed this process, perhaps lowering the ph and adding softer water (distilled percentage)? <After the sores are gone then the disease is practically cured. Now the fish needs to heal. Sometimes the fins get fungused too. These fungused fins to not regenerate. You will need to remove the fish from the water and clip the fins back to past the damaged area. they will then regrow but not as nice as if they were never damaged. Fins diseased back into the caudal peduncle usually do not regenerate.> The ten gallon does have a large filter, in fact its an old, fully cultured penguin 330 Bio-wheel, I shut this down for about 45 minutes every time I add medicine. I'm only changing water when the fish seems to be breathing harder than normal, should I be changing it more often? Any specific help is greatly appreciated. Thanks again!!! < Check the nitrates. The disease causing bacteria continue to thrive when nitrogenous wastes are present.-Chuck>
Silver Dollar Question 8/23/05
One more question please: after the sores are cleared, and their fins are clipped back, do I still have to quarantine them? Or can they go back in the 80 gal? < Put them back into the quarantine tank until the fins start to grow back.-Chuck>
Silver Dollar Problems 8/21/05
Ok, this makes sense, the silver dollars never had good fins from the day I got them with my used tank purchase, from what I understand they are quite old fish, around 5 years old. But no matter, I'm not too much worried about the way the fins look, as long as the sores close up. How do you suggest restraining the fish out of water? Under a towel, and I imagine this should be done in intervals of just a few seconds. Thanks for replying!!! < If you want to take them out to clip the fins then you take a large soft net and catch them. In a shallow dish you place a clean bath towel that has been soaked in the aquarium water. Catch the fish and place him on the towel and cover him up with only the section you want to work on exposed. Use fingernail clippers to trim the fins back past the damage. Silver dollars have very fine delicate scales that are easily damaged. If the areas get damaged then you might be back to square one.-Chuck>

Paralyzed Tetra 8/11/05 Dear Crew, <Stacy> The other day, I noticed that a tetra I've had with 3 others in a tank for over 2 years was lying on its side at the bottom of the tank.  I have no idea what caused this, and figured old age was kicking in, and he would likely die soon. <Likely so> The other fish are doing fine.  Today, it is still on its side on the bottom of the tank.  It is breathing, it's eyes are functioning and one side of its body is moving.  But that is all.  It's as if it is paralyzed on one side. <Happens> I have no idea what to do, and can't bear to let it suffer this way.  He's been this way for three days now.  What do I do? <It is likely not suffering, but if the prospect of this bothers you, you might euthanize this fish... in a bit of water, in a plastic bag... in the freezer>   And what is the most merciful way to put him out of his misery?  Or is there some way I can help him recover? <Probably will not recover... but there is always a chance> Any help you can offer is most appreciated... Stacy <Small tetras often only live a few years... Bob Fenner>
Re: Paralyzed Tetra 8/11/05
Dear Crew, Stacy> Thanks so much for your quick reply.  The poor little guy is still on his side breathing rapidly, with one fin trying desperately to swim, but no luck.  He's still at the bottom of the tank, gulping food when it comes his way.  The others are leaving him alone. I've had 4 tanks for 10 yrs and have never had this problem...It really baffles me. I'm going to go ahead and euthanize him if there's no improvement tonight, as I just feel like he is suffering, and he has been this way for far too long.  (I found your euthanization page online after a lot of exploration yesterday.)  Thanks for a wonderful, and very informative, site for all of us "novice fish enthusiasts".  I will be doing a lot of referrals to your site in the future!   Stacy <Life to you my friend. Bob Fenner>

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