I can't figure out what happened...

[julielynn47]

Hello everyone! I have not been here in quite a bit of time. I used to be here a lot, but life has its twists and turns and I kind of fell off the board.
Anyway, I want to tell you all what happened with my 75 tank about a week ago. Weirdest thing I have ever had happen in 38 years of fish keeping. I am not sure what to think of it. Maybe if this has happened to any of your tanks you can share what you know with me please?

My tank is a 75 gallon rectangle in shape. I have 2 canister filters going on it each rated for a 75 gallon tank. I know that might sound like overkeel but if one stops when I am not home, I have one still working, so it works for me.
My water perimeters are all perfect, exactly as they should be. The tank has been cycled for years and primarily it is just able to take care of itself with very little help needed from me. It is pretty heavily planted. I have to constantly pull out hornwort
and frogbit because those grow so fast, especially the frogbit, until it will black out the bottom of the tank if I don't. Those 2 get that dense. They are on one side of the tank and the rest of the tank has amazon swords, one big enough to leaf out over half of the tank itself.
So I feel that is pretty heavily planted. At least for me it is. The fishes have plenty of hiding spots in all the plants and drift wood.

Okay, that is my set up. Now on to the weird thing that happened.

2 weeks ago I went out of state to visit my son, dil and grandson. I had my daughter checking on my tank as well as my cats and dogs. As always things were pretty uneventful. That is until a few days into the stay with my son. My daughter called me very frantic. She was in tears and didn't
know what to do. She said she came to check all my animals and feed the fish. When she got inside the house and to the room that the tank is in she said all she could smell was death. She said she looked at the tank and pretty much saw nothing swimming and the water was murky and stank so badly.
She said this happened overnight as she and my grandaughter... So sorry! I hit the wrong button. I will continue...

 

[julielynn47]

Okay, she and my granddaughter had just fed the night before and everything was fine. She sent me pictures and all was well.
So overnight, the tank went from normal to catastrophe stage. She said all she could see were dead fish all over the bottom of the tank. She said there was some sort of white slime floating on top of the
hornwort and frogbit. the walls of the tank were covered in slime, just clear to white cloudy slime that smelled like fish.

I was across the country and could only talk her through water changes which she had never done before. I explained to her how to use the python water changer. she dipped out slime and changed the water twice,
and netted out dead fish. the she came back and did water changes everyday until I got home.

She said the fish that were still alive were acting very erratically and my bristle nose pleco even had his nose out of the water. she said most of the fish that were left were hanging out at the top of the tank
the cory cats were staying at the bottom but shooting to top and going back down I explained to her that they did that normally but not to the extent she said they were doing it.

It sounds to me as if the tank lost its oxygen level. I just don't know what to think about it. i have heard of ponds "turning over" and I am wondering if that is what could have somehow happened to my tank.

Have any of you ever had this happened and figured out why it happened?

 

[GaryE]

You aren't alone in having experienced an "I was out of town and everything died" event.

Threads here have been of the following types.

Overfeeding via kindness but inexperience;
overfeeding via kids wanting to help;
equipment breakdown and restarts, sometimes due to power cuts;
a large tank resident dying;
accidental poisoning via household products;
sheer rotten luck with nothing to do but reset with water changes.

It sounds like a biofilm growth took off, and that's usually over availability of nutrients and an at least temporarily lost cycle. That would also crash oxygen and spike ammonia.

 

[Back in the fold]

Somebody overfed . Overfed in a spectacular fashion . That’s my guess .

 

[julielynn47]

I thought of pretty much all you are saying. I figured I had lost my biological filtration. I just figured it was not cycled anymore and this was going to be a nightmare getting that beneficial bacteria reestablished.
But when I got home the first thing I did was test the water and all perimeters were perfect.

As to feeding I have those pill keepers and I load the food myself and all she has to do is open a section and put it in the tank. She has done this for years when I go somewhere and nothing has ever happened before.

my largest resident is my bristly nose pleco and he/she still lives! Thank goodness, I have had it since it was the length of my thumb nail. It is about 7 inches long now. I think it has gotten larger than they are expected to get.
I didn't lose a single cory cat or loach. I did lose a bunch of guppies, my glass catfish and hatchet fish. My daughter said the loaches were also hanging out at the top. Seems like, just going by what she told me, the oxygen level at the bottom of the tank maybe disappeared and the fish that were smart enough to hang out at the top were able to get oxygen. I don't know. Just weird. I have never had anything like this happen in all the years have kept fish.

 

[julielynn47]

You think overfeeding could cause something that catastrophic overnight?

 

[Back in the fold]

You think overfeeding could cause something that catastrophic overnight?

That’s the only thing I can think of . If the power went out and the filters stopped for a full day I can’t see how that would do it . Something added to the water is the culprit . I could very well be wrong but without seeing it that’s my half educated guess .

 

[julielynn47]

The tank seems completely fine now. I have changed both canister filters and did water changes myself this past week. Fish seem happier than I have seen them in quite awhile.
I have taken a lot of the floating hornwort and frogbit out as well and plan on keeping it under control a little better if I can. That frogbit just multiplies so quickly. I know I have a lot of baby guppies hanging out in that stuff.
Which is great, I love that all the guppies have actually been born in this tank. I started a few years ago with 4 female guppies, no males, and then a few months later babies started appearing. I learned that it very possible although I thought that could not happen. But I am here to tell you it did LOL Since those 4 guppies I have had an explosion of guppies. I thought maybe that might be a contributing factor to the disaster and so I just plan on not giving them as many places to hide.... as horrible as that sounds....

 

[julielynn47]

This is what my tank looks like now. I have pulled a lot of the hornwort and frogbit. This post disaster I will try to see if I kept any of the pics she sent me

 

[Back in the fold]

Interesting . Is it possible that your daughter was exaggerating when she described the “ smell of death “ ? Maybe it was only a swamp like smell which can happen if a filter stops . Too much Frogbit might inhibit the oxygen transfer at the water surface and add to that . Since you had no losses and things are back to normal maybe it wasn’t that big of a deal . Yes , this is interesting .

 

[GaryE]

I'm skeptical of water test kits. What they do, they do well, but they sell the idea water's perfect, when they only measure a few small important things. There's a lot they don't evaluate.

The accidental overfeed clue for me is the white stuff. Something has to feed it, and it has only ever appeared here in new tanks, tanks with new driftwood and fry tanks where I overfed.

 

[julielynn47]

I have some pics she sent me. I am waiting on them to load to the cloud and download to my pc. Then I will post them

I don't think she was exaggerating. The room still stank days later when I got home. The tank is in my bedroom. I slept with the window open with a fan in the window that night. The next day I went to work on the tank myself and cleared that all up.

 

[Innesfan]

Any chance the heater went rogue?

 

[julielynn47]

I thought about that. But I had it unplugged. I am in the south and we don't need it except maybe the dead of the winter. She checked and it was indeed unplugged. I told her to take it out anyway. which she did

 

[julielynn47]