Houseplant fell in my 65 gallon, 80% of fish died

[Hyde]

We got a weird frost warning ( June) and my mom wanted the patio plants brought in overnight. We have cats that eat plants so it got put on the top of the tank. During the night it tipped into the tank and I woke up to 4 flasher barbs, 2 dwarf rainbows, 2 balloon rams, 2 little loaches and 2 Siamese algae eaters dead. The three angels followed suit, then the remaining rams and all but 1 rainbow. 
I pulled it out immediately, too late. 
Netted my lost fish and did a 50% water change with double dose of prime. 
I believe it’s something in the soil, the plant was a gifted creeping Jenny fern. 
all that remains ( so far) is the Cory’s and the Otto. 
I’ve removed them to my other tanks. 
nothing was amiss with the api kit. 
Ammonia 0, Nitrite 0, Nitrate 20 ppm, ph 7.6, temperate steady at 79. Our water is always hard but they were all just fine until a stupid gifted plant had to be saved from frost. 
The tank is just sitting there like some harbinger of doom at the moment. 
I’ve pulled all the wood and put it in a full bath, it’s too large to boil. 
I’m devastated. 
Question, whatever was in the plant is obviously poisonous to fish. 
can I safely decontaminate the wood and plants? At the moment I cannot even begin to redo anything. I’m feel like a monster having tried to save them and just watching helplessly as they continued to die.  
Nothing showed up on the tests that would result in any of this. 
A week ago it was thriving and I’ve been hoping against hope that the water change would let the fish recover. The last few days have been awful. 
I’m trying to think of it as a lesson but this is a hard one. 
I’m assuming it would be wise to replace the substrate and thoroughly clean the tank, empty, start over. I’ve got hundreds invested in plants and wood and I’m just wondering if anyone has experience with this? Can anything be salvaged? I’m hoping the last few fish manage to evade water this is.  
My mom is 90 and feels awful about it, and I don’t want to make her feel worse, so having anything positive for a course of action would be helpful. 
Thanks in advance. 

[Hyde]

Oh yeah it’s a vevor external canister filter, 6 stages with ultraviolet cycle 660 gph. The toxic nightmare is probably all through it as well. 

[Tony s]

Oh wow. So sorry for your losses. Sometimes this hobby is just rough. And there really isn’t a lesson to learn there. Maybe not to use the tank as a shelf. Which we all do anyway. 
as for what was in the plant. Who knows. Could have been anything. Even mild pesticides. For cleaning whatever it is. Just a soak in the tub and a good rinse off should work for your hardscape. But how do you know for sure. If your plants are alive. I’d try and keep them that way. In a tub. Set aside from the tank. Think of it as a quarantine for them. Then I’d take the water way down to the substrate and vac it up really well. Possibly adding water back in and draining and vacuum it again. At some point you should be at almost a negligible amount of contamination. 
 

but after all that work, it’s really just a guess as to whether it’s gone or not 

[daggaz]

How was the aeration?  An oxygen crash would be my first suspicion, tho you do mention fish dying afterwards. 

Second guess, if it was a nursery plant, many nurseries include various forms of slug poison in their potting soils, some brands are nastier than others. In that case, a double water change of >90% is going to reduce the concentration to pretty much zero.  Let the water sit in the tank for 24 hours between changes if you can and you won't need to scrub everything, tho I understand if you want to anyway for peace of mind. 

But who knows, maybe your fish devoured a bunch of fertilizer pellets.  Doubtful, but you never know.  

[Sacah]

Sorry for your experience. Killing so many fish that quick, it had to be a fertiliser or pesticide. So it's just a case of diluiting it until it's not harmful anymore, so as Tony said, give things a few soaks and rinse and it should get it to a level that it isn't toxic anymore.

If you have activated carbon that you can add to your filter, it'll help remove any toxins around your tank, then just a few water changes.

It is a bit of a guess when it's safe to put life back in the tank, maybe a week of activated carbon and as large of a daily water change as you can, even 20% a day should get it safe after a week.

[Beardedbillygoat1975]

I second @Sacah’s recommendation for activated carbon and you could also consider Purigen. I think after that watching the remaining stock, plant and algae growth and monitoring for abrupt changes in nitrates etc. if it’s doing well in 2-4 weeks I’d start restocking very slowly. 

It’s very difficult when something out of our control leads to fish deaths. I lost nearly my whole fish room due to a power outage caused by a rabbit building a nest in my garage and ending up blowing a GFI and a breaker. Poof went my rate plexus, Corys and rainbows from some of my heroes in the fishverse. Ugly cries but I’m still here, slowly building back up but doing it smarter and saner hopefully. 
 

Have fun and take care of yourself. Recognize the impact on your Mom like you have helps. I screwed that up with my Fishwife and regret it to this day! 

[Dwight]

I had a 100G guppy tank outdoors (shout to Lucas Bretz @ LRB Aquatics for the idea!) that I successfully overwintered using Lucas' techniques only to have it completely wrecked last summer by Water Hyacinth I put in the tank.

Oh, that stuff was growing like crazy and was absolutely beautiful! Unfortunately by the time I discovered how invasive Hyacinth actually is, it had overtaken the tub, crushed my cycle, and destroyed the whole tank.

I'm trying again this summer, tub is cycled (again) and I put three Comets in last week

 

[Tlindsey]

On 6/22/2024 at 1:02 AM, Hyde said:

We got a weird frost warning ( June) and my mom wanted the patio plants brought in overnight. We have cats that eat plants so it got put on the top of the tank. During the night it tipped into the tank and I woke up to 4 flasher barbs, 2 dwarf rainbows, 2 balloon rams, 2 little loaches and 2 Siamese algae eaters dead. The three angels followed suit, then the remaining rams and all but 1 rainbow. 
I pulled it out immediately, too late. 
Netted my lost fish and did a 50% water change with double dose of prime. 
I believe it’s something in the soil, the plant was a gifted creeping Jenny fern. 
all that remains ( so far) is the Cory’s and the Otto. 
I’ve removed them to my other tanks. 
nothing was amiss with the api kit. 
Ammonia 0, Nitrite 0, Nitrate 20 ppm, ph 7.6, temperate steady at 79. Our water is always hard but they were all just fine until a stupid gifted plant had to be saved from frost. 
The tank is just sitting there like some harbinger of doom at the moment. 
I’ve pulled all the wood and put it in a full bath, it’s too large to boil. 
I’m devastated. 
Question, whatever was in the plant is obviously poisonous to fish. 
can I safely decontaminate the wood and plants? At the moment I cannot even begin to redo anything. I’m feel like a monster having tried to save them and just watching helplessly as they continued to die.  
Nothing showed up on the tests that would result in any of this. 
A week ago it was thriving and I’ve been hoping against hope that the water change would let the fish recover. The last few days have been awful. 
I’m trying to think of it as a lesson but this is a hard one. 
I’m assuming it would be wise to replace the substrate and thoroughly clean the tank, empty, start over. I’ve got hundreds invested in plants and wood and I’m just wondering if anyone has experience with this? Can anything be salvaged? I’m hoping the last few fish manage to evade water this is.  
My mom is 90 and feels awful about it, and I don’t want to make her feel worse, so having anything positive for a course of action would be helpful. 
Thanks in advance. 

Sorry for your loss. I agree about something in the soil. @Hyde

[Hyde]

On 6/22/2024 at 12:46 AM, daggaz said:

How was the aeration?  An oxygen crash would be my first suspicion, tho you do mention fish dying afterwards. 

Second guess, if it was a nursery plant, many nurseries include various forms of slug poison in their potting soils, some brands are nastier than others. In that case, a double water change of >90% is going to reduce the concentration to pretty much zero.  Let the water sit in the tank for 24 hours between changes if you can and you won't need to scrub everything, tho I understand if you want to anyway for peace of mind. 

But who knows, maybe your fish devoured a bunch of fertilizer pellets.  Doubtful, but you never know.  

I have an air bubble hose in the tank as well as an air stone so there’s aeration the length of it. 
I had been trying to get a peace lily transferred from soil to adapt to water and I still hadn’t figured out how to set it in place with only roots in the water, but after this I’m going to be side-eyeing plants and I’m not sure I’ll ever set it up. Slug pesticide is something I’ve never known about, yeesh!

[Hyde]

Thank you all for your compassion and insight. The wood is so big it’s in the bathtub, I’ll keep rinsing and soaking. I don’t know if I should add dechlorinator to the tub but I think I will. 
The plants I’ll set up a nursery tank for with water from my other tanks water changes. 
the rocks can be boiled so I’ll do that and clean the tank several times,

I think I’ll replace the substrate just to go the extra mile, I can’t deal with the fear of that poison resting there and undoing all the clean-up efforts. As for activated carbon I have a bin of it, as well as a purigen pillow. 
I'm not clear on if I should scrub out the filter and replace the biomedia stones, but I may do that too. 

I should ( I hope) have enough good bacteria to pull from the existing tanks to kickstart a new cycle when I get this all in place. 
On a somewhat positive note the corys and the Otto are zooming around in the smaller tanks. So far they seem to be ok. 
Thank you everyone. I’m very grateful for the time you took to advise me. 
 

[daggaz]

My reasoning for not being excessive about scrubbing all surfaces is this:

Whatever you got came from a house plant (most likely worst case in the soil) so there's not a huge amount of it; you didn't spill a jar of liquid pesticide in.  Whatever it is clearly got into the water column.  Most likely, it's a hydrophilic substance; most consumer poisons are because hydrophilic molecules are far more biologically available and likely to pass digestion without deactivation, easier to spread, and the latter also coincides with it obviously being up in the water column. 

So it's not going to really want to stick to surfaces.  Some physiosorption.  Equilibrium constant will strongly favor solution.   So empty the tank.  Flood the tank.   Wait.  Empty and fill again. 

Some chance it could remain in biofilms, then it could affect algae eaters.  So if you are nervous for your ottos: scrub it all down.  (You definitely don't need to boil anything and that won't necessarily deactivate the molecule.)  But if the algae is toxic, then all of your algae eaters are already dead.  I only see two siamese eaters on the list, and I doubt that's your entire cleanup crew.  Ergo, they got it in the water column. 

But it's your fish and your peace of mind, and scrubbing isn't going to hurt (other than deleting all your hard earned biofilms and good bacteria). 

[Hyde]

Valid points. I think the whole experience has made me jumpy about anything being a culprit. It’s going to be a while before I am in a place to buy new things for it. Currently I’m in school and we all know how expensive life is right now. I’ll follow your advise and go from there, thank you!

[daggaz]

Yeah that's honestly a good attitude.  Who really knows what it was. Nobody, that's who. 

Edited Saturday at 07:46 PM by daggaz

[TinaPax-Peeks]

My guess is the plant was treated with a Neonicotinoid which is a neurotoxin.

[Hyde]

Yeek! They were all thriving. It’s heartbreaking.