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Raising Discus Babies: Preventing the 30 Day Syndrome with Potassium Permanganate

by | Apr 16, 2019 | 5 comments

Preventing the 30-Day Syndrome with Potassium Permanganate


Today, we’re going to talk about the infamous 30-day syndrome and how to prevent it using potassium permanganate. In our hatchery we have a 200-gallon system and based on my measurements, we use two grams for the entire system. We’re going to show you how we do it in our system but remember one thing – this is for the professionals. These measurements are not for the hobbyists who have only one or two tanks because you can cook your fish with this chemical. You must take everything into consideration when using this method.

We are going to put the chemical directly into the sum because the sump pump is the one that’s going to put everything through the system and take it throughout. Why do we use Potassium permanganate? Very simple, Potassium permanganate will kill gill Flukes, external bacteria and remember, when they’re small, they’re vulnerable. So, we need this in order to prevent any deaths. And when baby fish start dying, it’s because there is too much bacteria in the system. What we do first is pour it right into the intake, and once it is pumping in you will see it as a purple color and it automatically comes right up through the system.


At this stage, this is a very active material that is right now killing bacteria. It will kill all of the flukes, bacteria and anything else that may hinder the babies in our system. We do this once a week, and It’s very important. A lot of you guys were asking me about this, and we are finally letting you guys in on our method for our central system. Now, keep in mind if you’re doing this in your home and you only have one tank, the formula changes completely. You must take that into consideration because this could be lethal to your fish if you do it wrong. Just remember that two grams is what we use for our 200-gallon central system.



How Long Do You Leave In The Treatment?


A lot of people call me up and say, “Hey Gabe, how much time do I leave the potassium permanganate in the water?” Well, the potassium permanganate will let you know when it’s done doing its work. When it is initially purple, it means that the chemical is active. Once it deactivates and is finished with its process, it will turn a different color – a tan, brown coffee color. This whole process from start to finish usually takes about 10 to 15 minutes.


Once that coffee color begins to appear, whether it’s five minutes or 20 minutes, that’s when you want to do your water changes. There is no set time limit for how long you should leave the chemical in the tank, It’s based on how long it takes for the potassium permanganate to deactivate. When you notice the color change and the chemical has deactivated you can now either do the water change or treat with the hydrogen peroxide, which will remove all of the potassium permanganate remnants.


In our 200 gallon system, I approximate that half of the bottle of hydrogen peroxide is going to go into the sum. This will clear this brown water and you’ll see it begin to clear up rapidly. It’s practically instantaneous. We add the hydrogen peroxide the same way that I put the potassium permanganate into the sum. The pump is going to suck up that hydrogen peroxide and shoot it right through the system and within minutes you’ll see how the entire system just clears up.


Some Important Information


In our system, some tanks may begin to clear up sooner than the others because the hydrogen peroxide hasn’t yet been fully circulated. Some of the lower systems where there’s not as much flow, the hydrogen peroxide hasn’t gone in yet or still has a slightly darker color. Eventually, the entire system will become crystal clear and this is how we deactivate the Potassium permanganate. Now, this is the way that we do it when we treat them on a weekly basis, but if you’re going to treat the following day because you’ve got a very, very heavy infestation of a bacteria and it’s killing your fish, you can’t use hydrogen peroxide. You must continue with the treatment three days in a row. This is a general overview of how we here at the Wattley Discus hatchery prevent the dreaded 30-day syndrome using potassium permanganate. Remember, this is for the professionals so don’t go based on the numbers that I gave you. If you’re going to do it at home just remember that everything is going to change drastically. We don’t want you killing fish, all right?

We’re here to help if you ever have any questions, so don’t hesitate to ask. I’m Gabe Posada and don’t forget to look for us on all the social networks because we’re there and thank you for being here with us!



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Wattley Discus Admin


  1. Suman Dasgupta

    I keep fishes by hobb. Ar present I have two discus fish in my tank. One isadult, aged 3 years in my tank, and the other has spent 1 and 1/2 year here, not fully grown but adult. Recently the second have caught some problem and is not eating for about a month now. I sispect it has some gill fluke (parasite). Also it has a velvet like layer on it’s skin which is observanle under close watch. It often tries to rub itself on the wall. It has appetite but whenever it tries to eat some sort of itching problem irritates it, it starts flapping on of it’s wing rapidly and then run to rub itsel. Things were fine with the big adult one, but two days ago I noticed it caught white spots on it’s skin. Right now there are only five spots. I raised the temperature now to 30° C. My question is can I treat with potassium permanganate? What is the dose. My tank is 180 litres. For how many days I have to continue the treatmen? And when should I chamge the water? I dont have hydrogen peroxid.
    Would be obliged to get some help.

    • Tobin Gibson


  2. Joost Jalink

    Dear sir!

    Here is a message and question from the Netherlands! 🙂

    I have discus fry that are 4 weeks old. Today 1 died (1 of the 51) wen I did my research on this I came passed you’re website.

    I saw you doing this pp method on discus fry and my question is what is the formula per liter? I see a lot of different opinions about this but since you are the pro I hope you can answer.

    The fry is eating beef hart as prime food 7 times (small) portion a day and I do 80% water change every day.

    There in a 90liter aquarium for now and if they grow a little more I move them to a bigger tank with 350liters.

    You said that the amount of pp you are using is for 200 gallons and if I use it in 1 aquarium the formula chances drastically, so I hope you can help me out!

    Kind regards,

    Joost Jalink
    From the Netherlands

  3. Patricio

    I have fry discus in 300l aquarium how much mlg I need to treat cz i lost 5 of them and some of is black
    I do 25% every day and vaccum and 50% mu ph 6.5
    Tds 165 T 30C


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