All my fish die overnight! :(

  • #1
skip to bottom of post if you just want the question without having to read.

Let me start from the beginning. Tank history-

Problem 1:Ammonia(solved)
We have a 10 gallon tank that we are just starting up. It ran on its own for 5 days before we added guppies for cycling. (maybe this is normal. I've heard cycling fish are sacrificial fish?) We started off with 3 female guppies, a large one, a really small and scrawny one and an average sized one. (was not thinking about size differences at all when we bought them.)They were fine for a couple of days (at the time we were using goldfish conditioner since we originally planned on having a goldfish before we learned about tank size/messiness issues.) but then they started laying on the bottom of the tank. At that point I figured there was an ammonia issue so I bought a kit and started doing 20% water changes every day. Then the average sized fish started showing signs of ammonia poisoning so I put her in a small tank I had from very long ago with fresher water mixed with some tank water. Meanwhile did a 50% water change in the 10 gallon and used prime instead of jungle start right as advised by the lovely members of fishlore. She seemed totally ok after the water got better. Tank stabilized for a little while and we had some fry.So I walke to the LFS and got fry food and a TON of hiding places. Unfortunately they all ended up getting eaten eventually.

Problem 2:Bullying(solved)
Then the largest guppy started bullying the other 2 to the point where she wouldn't let them eat. We were advised to get some males so I got 2 males and another female to balance the ratio. (over the course of these few weeks the smallest fish kept getting smaller and smaller and at this point she appeared to have a slightly bent spine.) One of the males was swimming into the filter for hours. Not the current away from it, but the one that should have been pulling him towards the filter. He just kept rapidly swimming in that one spot. The next day I found him dead. (could not have been ph shock since I acclimated with the one cup in one out method for 2 hours.) The only thing I can think of was that there was a drastic temp drop in my brother's room that night bringing the tank from 82F-68F in about 10 hours without us knowing about it. We also found out that the 4th female we bought was actually an extremely aggressive male. Another possible cause? We returned the dead fish and the aggressive one and did not get more leaving the 3 original females and one male.

Problem 3: what the heck just happened?!?
The LFS said our water was great other than being a little high on the ammonia and having very low ph. (like so low its not even on the test.) She advised us to get ph buffer and showed us her favorite brand. I heard it was bad to use chemicals but she said she has been using it in her fish tank for years and it's the better option in a case where our natural ph is so low. Because of the unstable temps in my brother's room I bought a stand and moved it into my room. I did a 50% change to make the tank movable and added the prime and ph buffer. Temps were the same whenever I do water changes. The male started darting around the tank rapidly. Internet said it was chlorine so I added a little extra jungle start which specifically focuses on eliminating chlorine. At this point all the fish seemed happy and calm except for the small one that was still really scrawny. It was hard to get her to eat. I saw what I thought was a tiny white patch above her eye but it was so small, didn't look like any known fish diseases and everyone else said they didn't see anything so I thought maybe I was just crazy. That night she stopped swimming around and just kept darting upwards and then falling down over and over again for hours in the same spot. I thought she would be dead by morning but was not. She just moved to a different part of the tank. All the fish were still fine except her. When I got home from work that night she was stuck to the filter dead so I netted her out and flushed her. Anyone know what was wrong with her? (There is a video in my "official hello" thread on the welcome page.) Anyway. After netting her out I noticed that someone left the light on and the tank temp was high. I turned the fan on, light off and took the lid off the tank ion an attempt to cool it down. I also noticed that the fish that were totally ok 5 hours ago when I left for work now had what appeared to be the same tiny white patches on them that the other fish had but mostly on their fins. The male's fin looked cloudy white and the large female's tail had very obvious chalky looking white streaks through it. (her tail was black.) The third fish showed very little signs of being sick other than the tiny white patch on her fin. (it looked more like a flake of human skin than any kind of fluffy fungus.) A couple of hours later they were all lying around not swimming except for the male who appeared to be fighting it.(he was attempting to swim but just floating around very unnaturally.) At this point all stores were closed and I knew it was all over. -insert crying fit here- When I woke up the next morning they were gone. All three. I did water testing and temp/ammonia were normal...better than ever actually. I do not have a ph/nitrite test kit so did not get those readings.

What I am asking now is 1.What do you think killed them so I can prevent it from happening again and it possible to disinfect the tank without killing all the good bacteria and having to start the cycle all over.
The water is currently at a place where its been cycling for 4 weeks and the ammonia killing bacteria have grown. Nitrite spike would be coming up next.
If it is possible to kill bad bacteria while keeping good. How do I do it? Thanks for the help in advance.
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  • Thread Starter
  • #2
Also when it comes to disinfecting the tank, I do have one live plant in there. What should I do with that?
  • #3
Sorry to hear about the loss of your fish. As a fellow newbie to fish keeping, it can be frustrating to know if we are doing the right thing to keep our fish healthy.

First question. How are you testing your water? What kit are you using? Are you using test strips or a liquid test? If you are using strips, they are inaccurate. You need a liquid kit. Most people use API master kit.

Second. You mention that your tank has been cycling for 4 weeks. You also say that you don't have ph/nitrite kit. Without a kit to test for nitrates and nitrites, there is no way to know if your tank has any beneficial bacteria.

Lastly, if I understand correctly, you no longer have any fish in your tank. If you have no fish, you have no ammonia. Ammonia is the food source for the beneficial bacteria. Without that food source, the bacteria will die.

Your fish probably died because your tank was not cycled and they were exposed to harmful ammonia. The only way to prevent this from happening, is to cycle your tank before adding fish.

I don't know how to add links to this post but research the following topics on this site: nitrogen cycle, fish less cycling, cycling with fish using TSS.

Also, not sure why you want/need to disinfect your tank. If you do disinfect your tank, any beneficial bacteria will surely die.

Hope this hels and good luck
  • Thread Starter
  • #4
Thanks for the help.
I am using API liquid test kit to test ammonia. A couple of hours after I took the dead fish out it was at 0. (It has been pretty stable so I don't think it was the ammonia that killed them. More likely that I just had the nitrite spike and had no way of telling. ) Should I "feed the tank" or is it too late for the bacteria? (its been about 12 hours without fish.)
My reason for disinfecting the tank is the white stuff on the fish. I don't know what it was what caused it and how contagious it was. It did not look like ich or any type of fungus. The stuff above the questions should help but I know it's really long.
  • #5

I'm so sorry about your fish.
It would be my guess that they succumbed to being exposed to toxins from cycling (you mention high ammonia) along with a pH buffer and temp drop.
All of that just weakens them to the point they cannot cope and get sick.

Imo, there should never be any "sacrificial fish"
That's just cruel when there are ways to cycle without harming fish.
It's sad that so many of us received bad info and started off that way.
  • Thread Starter
  • #6
Lucy do you think the tank has any kind of dangerous illnesses or can I just finish the cycle as is? (wish I knew what the white stuff was....wish I had pics. It was really weird. Like the fish had dandruff or something.) Thanks for the help guys.
  • #7
White stuff, like a fungus? Was it on the mouth or body? Did all the other fish have this? If so it's quite possible you got infected fish.
  • #8
I'm not sure I'd worry about sterilizing at this point especially if your going to continue cycling without fish in the tank.

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