Unknown Fungal Disease

Hello everyone, I have a serious emergency that needs to be discussed right away.
I recently just bought a 20 gallon tank after having a 10 gallon tank for about a year. 
After letting the tank cycle for about a week introducing fish food every day to help quick start the cycling, i added my guppies(4), platys(2), high-fins(2) and corydoras(2). 
Shortly after my guppies had babies i transferred the babies over to the 10 gallon tank and kept the others in the 20 gallon tank. about a month into the new tank my guppy developed Dropsy, showing signs of the pineconed scales. After realizing immediately what she had i went to Petco, bought aquarium salt and gave her a salt bath for 30 minutes. This helped with the swelling and such. I put her back in the tank (bad idea) and continued to give her baths every other day and treating the rest of the tank with Microbe-lift? I think that's what it was called but it was for fungal and bacteria diseases and it was an all herbal medicine. After a week of treating her I realized the other 2 female guppies were acting weird. One of them had a bulging eye, the other looked sluggish and was at the top of the tank breathing hard and didn't do much. This was also when i realized the guppy who had dropsy was starting to show signs of white growths on her body. It looked like white soft fluffy scales in random places. And my males fin was rotting on the ends. I checked the parameters of the water and realized the pH level was 6.0 which is considered acidic. I panicked and used my pH drops to level out the pH and increase it and i turned the temp up. The next morning, I found all my guppies floating like a ghost covered in slime and white patches on the end of the tails floating lifelessly, along with my corydora, one of my platys was alive and had the white patches on the end of the tail and the other platy was alive and hiding. I found my other corydora alive in the corner and the two high-fins were hiding but one of them was super skinny and had the white patches on tails as well. I immediately got the fish that were alive out of the tank and put them in the 10 gallon tank. I immediately removed the 2 that had white patches on them and put them in a salt bath while I went to petco and talked to my fish lady. I told her the horrible news and she suggested I did a vinegar wash to my entire 20 gallon tank and soak everything in vinegar and water and start completely over. She also said I should euthanize the ones that look sick who were in the salt bath because they would die soon. We couldn't figure out what killed all of my fish but she gave me a bacteria and fungal medicine to treat the water in the 10 gallon with to help prevent the disease to spread to the babies in there. Well a few days have passed and I woke up this morning and found 80% of my baby guppies stuck against the filter with the same white spots on the tail covered in slime. They all started dying one by one each hour. It then spread to my high-fin babies and im scared it will spread to my full grown fish whom are staying in there with them. The plan was to keep the full grown ones in there, treat them and eventually move them over to the 20 gallon once it cycled for 2 weeks. But i'm worried it won't be long before they are gone too. None of them have any white spots on them and they seem okay, the high-fin lays on the bottom majority of the time and will come up later and then lay back down. The platy hides in his house and doesn't ever come out. And my albino corydora always on the bottom obviously and he eats and stays under his plant. 
 
the ultimate question here is... what the heck is killing my fish so fast and should i put my corydora, high-fin and platy in the new tank once it cycles if its been in this water for some time when I don't know what's killing my fish, because I don't want to contaminate the 20 gallon by putting them in there not knowing if they are infected or not. 

Can someone please describe columnaris because i'm scared I have this in my tank. 

Hi, Please can you give us the following information for you tank
 
Ph 
Ammonia
Nitrite
Nitrate 
temperature
 
This information will help us to help you. 
 
From what I have gathered from your OP you have soft acidic water which is perfect for your corydora but bad for guppies and platies. Guppies really need hard alkaline water, platies also do better in hard water.
 
I suspect that what you have is an uncycled tank and the problems you've seen are from ammonia burns but if you can provide us with the stats we can go from there. If you don't have a water test kit I suggest you get one as you will need it. The liquid drop test kits are what we recommend as the strips are very inaccurate. The kit most widely available is the API masterkit. This will give you tests for all of the main things you need as listed above. 

Well, that is a terrible story. It's never fun to have a dead fish but this? This is like a horror story.
 
At first, take a deep breath and don't panic. Before I will try to help you figuring out what is affecting your fish I need to ask some questions. 
Can you give the exact water parameters?
Can you provide a picture of a fish that is ill?
 
One of the most important causes for fish diseases is stress. In your case the development of stress didn't help. By giving them a salt bath every day you have to capture the fish, which causes a lot of stress. Not only to the fish that you caught but also to the other healthy fish. This higher level of stress might harm a lot. You healthy fish will have a higher chance of getting ill and the fish that are all ready ill will become even worse.
Furthermore, don't randomly transfer your animals to other tank as this causes a lot of stress as well.
 
Another thing to note is that corydoras species need to be kept in groups of 6 or more. Otherwise they will become stressed as well. Besides that was the cycling period too short. Cycling takes a minimum of 3 weeks and preferably even longer. So the fish that float near the surface might suffer from ammonia or nitrite poisoning. In case you didn't cycle the 10 gallon tanks for 3 weeks either you should do daily water changes.
 
After having said that, it is hard to determine what illness your fish are dealing with. A picture will tell us more then 1000 word could ever do. However, based on your description I will take a shot. As you said, a lot of your fish had suffered from dropsy. One of the symptoms of this is that fish can develop a white slimy substance around the scales. So it might be a fast spreading form of dropsy. As Dropsy is mainly caused by stress, which in your case sounds plausible, it can be easily prevented. By fulfilling the needs of your fish you can avoid getting dropsy in the future. So make sure that they get fed properly and live in a tank with enough hiding places. Besides that do you need to make sure that the water parameters are acceptable and that the fish are kept with enough specimens. 
If it is indeed dropsy, your fish will most likely die. However, this doesn't mean you cannot do anything at all. At first, don't add new fish until all your current fish are healthy. Secondly, try to give the fish a better tank to live in. Are there enough hiding places? are the parameters ok? Next, as (almost) all your fish are sick you can treat them in the tank they are in now. For this you can add a little bit of salt (not too much, 1 teaspoon per gallon max) to the water. Furthermore, you could buy antibiotics. If you use antibiotics, remove the carbon out of your filter. But again, I'm not really sure whether it is dropsy before I've seen a picture.
 
Hope it helped.

Thank you guys for responding fast, I have taken photos and taken water parameters as well:
Nitrate- 0
Nitrite- 0
Hardness- 150
Chlorine- 0
Alkalinity- 0
pH- 6.2
 
The following images are of the guppy who had dropsy in my 20 gallon who passed away the night before the huge fish suicide: IMG2394
And this was the 20 gallon tank before everyone died: IMG2524
And these are my fish who survived and are now in the 10 gallon tank: 
The black and yellow fish is the high fin and the albino pink fish is my corydora and my red fish is laying in the red plant hiding and that is my platy
 
you'll also see my high-fin babies laying next to her mom!
The last images are graphic because they are the baby guppies who died, the bottom one was found sucked in the filter and the other one was laying on top of the heater. 
Notice the white film/spots forming on the end of their tails in the picture of the heater.
And I have one of the high-fin babys from an over head shot with a white spot on its back 

Bubbelzzz said:

Well, that is a terrible story. It's never fun to have a dead fish but this? This is like a horror story.
 
At first, take a deep breath and don't panic. Before I will try to help you figuring out what is affecting your fish I need to ask some questions. 
Can you give the exact water parameters?
Can you provide a picture of a fish that is ill?
 
One of the most important causes for fish diseases is stress. In your case the development of stress didn't help. By giving them a salt bath every day you have to capture the fish, which causes a lot of stress. Not only to the fish that you caught but also to the other healthy fish. This higher level of stress might harm a lot. You healthy fish will have a higher chance of getting ill and the fish that are all ready ill will become even worse.
Furthermore, don't randomly transfer your animals to other tank as this causes a lot of stress as well.
 
Another thing to note is that corydoras species need to be kept in groups of 6 or more. Otherwise they will become stressed as well. Besides that was the cycling period too short. Cycling takes a minimum of 3 weeks and preferably even longer. So the fish that float near the surface might suffer from ammonia or nitrite poisoning. In case you didn't cycle the 10 gallon tanks for 3 weeks either you should do daily water changes.
 
After having said that, it is hard to determine what illness your fish are dealing with. A picture will tell us more then 1000 word could ever do. However, based on your description I will take a shot. As you said, a lot of your fish had suffered from dropsy. One of the symptoms of this is that fish can develop a white slimy substance around the scales. So it might be a fast spreading form of dropsy. As Dropsy is mainly caused by stress, which in your case sounds plausible, it can be easily prevented. By fulfilling the needs of your fish you can avoid getting dropsy in the future. So make sure that they get fed properly and live in a tank with enough hiding places. Besides that do you need to make sure that the water parameters are acceptable and that the fish are kept with enough specimens. 
If it is indeed dropsy, your fish will most likely die. However, this doesn't mean you cannot do anything at all. At first, don't add new fish until all your current fish are healthy. Secondly, try to give the fish a better tank to live in. Are there enough hiding places? are the parameters ok? Next, as (almost) all your fish are sick you can treat them in the tank they are in now. For this you can add a little bit of salt (not too much, 1 teaspoon per gallon max) to the water. Furthermore, you could buy antibiotics. If you use antibiotics, remove the carbon out of your filter. But again, I'm not really sure whether it is dropsy before I've seen a picture.
 
Hope it helped.

Click to expand...

I forgot to quote this in my previous comment! I hope the info i gave was helpful for you to try to see what's going on with my fish!