Deadly Fast Spreading Fungus...Please Help!!

[Essjay]

That converts to 125 ppm. Something in your tank is increasing GH from 125 to 200 ppm.

GH is the amount of calcium and magnesium so adding sodium hydrogen carbonate (baking soda) won't increase GH as it doesn't contain them. And as Byron has already said, Seachem Alkaline Buffer increases pH and KH but not GH.

So what is increasing the GH in the tank?


Just a thought - does your tank suffer from evaporation, and you top it up with tap water?

 

[Silencedogood]

Just a thought - does your tank suffer from evaporation, and you top it up with tap water?

All the time. I'm replacing water weekly from evaporation.

 

[Essjay]

Ah, that explains it.

When water evaporates, it's only water. Everything dissolved in the tank water stays in the tank. This includes the GH minerals. Then you add water which contains more GH minerals. Then you top up again and add even more GH minerals. The effect is ever increasing levels of calcium and magnesium. Yes, water changes do remove water with extra minerals and replace it with tap water level minerals, but this just slows down the increase a bit rather than stop it.

If you need to top up between water changes, you need to pure pure water eg reverse osmosis water as pure water has nothing dissolved in it.

 

[Byron]

My tap water is 7 dGH

OK. GH of 7 dGH is equivalent to 125 ppm GH. This needs to be increased for livebearers, at least to around 12 dGH [215 ppm] given that you have mollies which are especially vulnerable to low GH. The only way to increase GH is with the addition of the hard minerals, calcium and magnesium. You can use products like rift lake mineral salts--and "salt" here is not common salt sodium chloride, but mineral salts, just to be clear--which requires preparing the water for water changes external to the aquarium. Or a calcareous substrate of aragonite sand.

The low GH is slowly weakening the fish, and along the way issues (disease for example) will more readily inflict the fish because they are in a weakened state. There is no external sign of this until it has become so problematic for the fish to perform its basic physiological functions that it literally drops dead, or may die from other causes along the way.

EDIT. Essjay posted as I was typing. It would be preferable to have the GH of the water established by a more stable means, long-term. All these chemicals going in are affecting the fish too, another side effect.

 

[Silencedogood]

So all of current livebearers in my main tank are or at least appear to be very healthy (except for two mollies that I added the other day). I am selling their offspring and they don't have any issues. The guppies that have the fungus are the ones in my nursery tank. Whenever I try to add them to my main tank, they break out with this fungus. I'm treating the whole 10 gallon tank now but I was just wondering why it was happening when they showed no previous signs of illness?

 

[FishGuest5123]

Read up on columnaris and see if that could be your issue.

 

[Silencedogood]

Read up on columnaris and see if that could be your issue.

It seems possible. The fungus first eats away their tails and fins and then moves along their body. The fish typically die when it is halfway up. What causes columnaris?

 

[Byron]

We do not know that fungus is the issue. Colin asked for photos, without which we are guessing, and that always runs the risk of making things worse. And the fish again may appear fine externally, but that does not mean they are in good health. Unless you are a biologist and perform a necropsy you cannot assume the fish are in good health when the environment is not providing what they need.

Columnaris would likely be evident on fish living in the tank. It certainly was the one time I introduced it with new fish. And it appears as blotches or patches on various parts of the fish. I cannot say it could only start on the fins, but this is not my understanding of the disease. I consulted a microbiologist at the time, and she noted that there are many forms of bacterial disease that bear very similar external signs but may be quite different.

 

[Silencedogood]

I'm going to try to get some pics; I have very bad lighting in that tank.

 

[Silencedogood]

 

[Silencedogood]

This is what ends up happening. But it starts with the fins and tail and them moves up the body. I'm not sure what to do with this fish. It's still alive but it's suffering.

 

[Colin_T]

It is a bacterial infection but it is not Columnaris, which starts on the mouth and face.

Try a broad spectrum fish medication that treats, fungus, bacteria and protozoan infections. If that doesn't fix things in a couple of days, look for an anti-biotic.

You can add some salt to the tank too with the medications. If there are only livebearers in the tank, add 4 heaped tablespoons of salt for every 20 litres of tank water. If there are other types of fish in the tank, only add 2 heaped tablespoons of salt per 20 litres.
Keep the salt in the water for at least 2 weeks but no longer than 4 weeks.

 

[Silencedogood]

@Colin_T Is it fungus?
I am using API Fungal Cure. The active ingredients are Victoria Green B and Acriflavine.

Is there any reason why it showed up only when I added them to my main tank?

I have salt in my tanks but not that much because I have live plants.

 

[FishGuest5123]

Colin said it was bacterial, not fungal. I’d try using Furan-2 if you can get it. It treats bacterial diseases.

 

[Colin_T]

No it's not fungus.

The Acriflavine might help but Malachite Green (Victoria Green) won't. Malachite Green is used for external protozoan infections and does nothing to fungus or bacteria.

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The bacterial infection would have been brought in on the new fish.

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I would increase the salt. Most plants can tolerate some salt and unless you have rare plants, I would just replace any plants that die. Rare or expensive plants can be moved to a quarantine tank and treated there without salt.