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3 years with Neon Tetra Disease

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I set up my 75-gallon planted tank in December 2019.  Since that time I had about 40 Neon Tetras at once.  Some were bought from my  LFS and the rest were from an online order sometime later.  I've had Neon Tetra Disease (NTD) in the tank for years but it only clicked that it really was NTD probably six months ago.  As you'll read in many articles, and from the coop, most people don't actually have NTD and they have something else.  So I wanted to share my observations of having that disease in my tank for the past few years.

The tank 

  • Neon Tetras 
  • Panda Corys 
  • Red Cherry Shrimp 
  • Snails
  • Heavily Planted

How I know I have NTD

Well, it's sort of embarrassing that it took me years to realize that I actually had NTD but here is how I arrived at this point.  My fish would occasionally die off and I didn't think much about it.  I've had the tank for years and some are going to die over that time.  I bought a decent amount of "jumbo" tetra's so I figured they were older and all that.  However, fish were developing growths on their body. 

From what I've seen in my fish there is usually either growth around the mouth that get extremely large or there is growth from inside of the fish.  The growth might be near the middle of the fish or towards the end of the tail.  When I started noticing the growth I did provide medication.  Over the years I've used Mardel Maracyn, Fritz paracleanse, and even some API products.    Obviously, this stuff never helped as I misdiagnosed NTD but I did attempt to treat the fish the best way I knew how. 

Another thing to mention about the growth, which is a key identifier that I overlooked initially, is the growth looks hard.  It's not some soft fungus growing on the fish, these are hard lumps on the fish.  Their shape doesn't change (except get bigger), they don't look squishy, they are solid.

Aside from the growths that I witnessed the fish would start to lose its color 1-3 days before death.  They would go noticeably pale to where you knew that fish was in trouble.  At this point some fish may not be able to swim like normal.

Didn't it wipe out all of your fish!

No, not really.  There was never a mass die-off or a big event where I lost a ton of fish.

Out of the 40 fish I still had around 16 as of a few months ago (more on that soon).  I still have Neon Tetra's in the tank and some of them are the same jumbo ones that were the first ones I bought three years ago and they look fine.  I have no doubt that all the Neon Tetra's have the disease at this point. So I can say with confidence, at least with my setup, NTD doesn't immediately wipe out all fish.

When I realized it was NTD, I euthanized early

Of course I don't want fish to suffer, and over the years I've euthanized some unhealthy fish with Clove Oil (I highly recommend it, my fish never visibly struggle and just eventually fall asleep.  If your fish thrashed doing this you did it wrong.)  However, about five months ago when I realized it was NTD and I knew the outcome for the fish I decided to finally be proactive about it.  There were a few fish that had growths on their body and I decided to catch them and euthanize them.  They would have lived for many more weeks as the growths were small and just starting to develop but I knew the outcome.  Over these five months I've euthanized about 8 or 9 in two separate batches.  I still have about 8 tetras left without showing visible signs of NTD.

How did NTD spread?

I learned that NTD spreads from fish eating parts of dead infected fish floating in the water column.  You see, my tank has 150-200 Red Cherry shrimp, snails, and is a very active tank.  When a fish died, it would be eaten within a day.  I saw no harm in leaving the fish in there as it was food for other animals and quickly was dealt with so, in my eyes, the chance for any negative impact to the tank was minor.  A dead tetra wasn't going to throw off my balanced tank.  So, I assume that as bits of fish were floating other fish ate it and got the disease.  As I've stated, I didn't know it was NTD for years.

Has NTD affected other fish in the tank?

I have Panda Corys and I haven't lost a single one, ever.  In fact they had babies who have grown up and are little adults of their own. I also have a few Endlers and they are so small I really wouldn't be able to tell if they ever had growths or not, I never noticed any growths on them.

What now?

I'm just letting the Neon Tetras live out their lives.  I periodically check the tank to make sure there aren't any visible or concerning signs of NTD, and as long as there aren't I'm just letting them be.  When I see signs of NTD, I'll euthanize the fish.  

That's it!

Maybe this will be insightful for someone, or maybe not.  Either way, I wanted to post my experience so if anything someone can learn more about NTD.  Thanks!


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Great write up lots of useful information It's a common misconception that Neon tetra disease only affects neon tetras it has also been found in  angel fish goldfish danios Rasboras barbs other types of Tetras such as cardinals rummy nose tetras and guppies as well it has symptoms that could be mistaken for other disease  that why I think a lot people misdiagnose  this disease  @ZoeyFish

Edited by Colu
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  • 2 months later...

Thank you, @ZoeyFish, for posting your experience. I have been wondering what to expect with the lifespan of my afflicted tetras who I moved to a "hospice" tank several weeks ago and came here to search for a timeline. I guess I expected them to die off quickly once the white lumps started up, but that has not been the case. 

I have purchased clove oil in case I need it, but I've never used it so am scared to get to that point. 


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Just for the sake of sharing, if anyone hasn't seen this, here is Cory's take:


On 5/28/2023 at 2:04 PM, PineSong said:

Thank you, @ZoeyFish, for posting your experience. I have been wondering what to expect with the lifespan of my afflicted tetras who I moved to a "hospice" tank several weeks ago and came here to search for a timeline. I guess I expected them to die off quickly once the white lumps started up, but that has not been the case. 

I was reading the thread earlier. I'm very sorry for what happened and what you and the fish are going through. It's tragic, and I've had similar experiences with tetra and rasbora species. I'm apprehensive for certain on those two families of fish because of it now. I'm much more concerned with quality because that is all I can assume was one of the causes. 😞

Hopefully things go OK and you're able to keep the disease from spreading.

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Thank you, that is my hope as well. Ironically, even before this disease showed up, I had decided not to keep neons in the future after these lived out their lifespan. They are a bit flashy for me and I prefer to let my livebearers be the flashiest fish in my tanks.


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