Sudden fish deaths .

[Annie]

All of a sudden all my fish are dying. Just when I thought it was stable and doing great. 
the power went out one night for probably For only a few hours. That’s when I noticed the first couple fish died after that day. It started with an Otto. Then my clown pleco. 
I added some conditioned water and some aquarium salt that is supposed to be beneficial to sick fish. Next day more fish die. A couple days later I do another water change with more aquarium salt thinking this will help before I do the change I checked the levels and The ammonia was slightly high. How did that happen when I thought my tank had already been cycled. For years now.

yesterday I removed the filter and added the tablets for ick treatment. More dead fish. This morning I added two more tablets. It’s so sad to see them struggling and I’m trying to save my Coreys and tetras now and one silver tip left. 
Another thing that might be the issue is I’ve seen that scented candles can affect them and I also bought new incense that is resin-based is this an issue is this what is killing them? My plants were looking great and my fish were looking great and now all of a sudden everything‘s going downhill😢

what to do?

please help, Annie 

My roommate who thinks she’s knows everything is convinced it’s the salt . even though I added that after the first 2 deaths 

[MattyM]

I'm so sorry @Annie - that sounds so stressful. How often do you do water changes? I'm not too familiar with it, but there's something called Old Tank Syndrome - if you google that you might find some good info to see if that sounds like what you're dealing with. 

Can you share any water parameters with us? That would be a good place to start. 

Also, do your fish seem to have ick? If not, I would stop treating for it.

The ammonia spike could be from the dead fish, and/or your cycle crashing. If your cycle is crashing, FritzZyme 7 will help. 

[Schuyler]

Sorry to hear that you're losing your fish.

It sounds like it could be stress related. 

My guess is that they were stressed out by something and the power outage changed the temp and lowered O2 levels enough to be too much for some fish.

I did a similar thing when I was getting started where it caused a chain reaction.

Your best bet is to try and stabilize things. When you do water changes try to keep things as similar to what is in the tank (temp, salt amount, etc).

What meds did you use? Do you see anything visibly wrong with them? Meds can mess with bacteria in the tank and throw off your cycle.

Do you have a way off adding more aeration?

Do you know how long the dead fish were in your tank? Are you sure all dead fish are out? That can spike ammonia pretty fast.

Edited December 8, 2022 by Schuyler

[venzi]

make sure the salt is diluted in water and you slowly increment the dosage until you reach your desired amount.   Like if your target is 5 tbsp per 10 gallons, then slowly raise it over time over days or hours - like 1tbsp per hour or something.  

[RichNJ]

Not sure it helps but I had an air pump on a sponge filter on a bare bottom tank die on me overnight a few weeks ago.  I noticed in the AM a dead fish and other gasping.  I tested and ammonia and nitrite spiked since no water was moving through the beneficial bacteria.  I did a large water change, added Prime and hooked up a spare pump.  This Got the tank normalized and ammonia and nitrite gone for good within 2hrs.  Got to love chemistry!!

So maybe check the standard parameters to rule out that.  

[nabokovfan87]

First, welcome to the forums.
 

On 12/8/2022 at 11:47 AM, Annie said:

the power went out one night for probably For only a few hours. That’s when I noticed the first couple fish died after that day. It started with an Otto. Then my clown pleco. 

Whenever the power goes out I like to add an airstone for at least 24-48 hours just to help the fish recover.  It's stressful I would imagine.  Oto and some plecos can be sensitive to temperature and oxygenation.  Can you share a bit about the setup as well as any test results (including temperature) for your tank.
 

 

On 12/8/2022 at 11:47 AM, Annie said:

yesterday I removed the filter and added the tablets for ick treatment. More dead fish. This morning I added two more tablets. It’s so sad to see them struggling and I’m trying to save my Coreys and tetras now and one silver tip left. 

Why did you start treating for ick? did you see white spots on any of the fish?  Does the tank currently have a filter?

Edited December 8, 2022 by nabokovfan87

[Annie]

Thanks for the responses and helpful video.

I was letting my tank stabilize when we had a big snowstorm and lost power for four days. 🥶🐟🥶Very stressful for me and my fish. Power is back on and four of them made it through. I’m am now looking into a battery operated back up system for when this happens again.. something that can operate the filter, air stone ,and heater and lights. Are there any suggestions? I’m doing a search on Amazon right now.

One more thing is the one bronze Cory that made it looks like his tail fin being chewed up?? 
Annie 

 

[Schuyler]

On 12/14/2022 at 4:40 PM, Annie said:

Are there any suggestions? I’m doing a search on Amazon right now.

One more thing is the one bronze Cory that made it looks like his tail fin being chewed up?? 
Annie 

 

I don't know if anything that would keep all that running for four days... A UPS may keep it running a few hours maybe. Aquarium Co-op has a USB powered air pump that you can at least keep things aeratioed for a bit.

Your Cory may have fin rot. It's there a white edge on the "chewed" portions?

[Flumpweesel]

Have you got rid of the ammonia, that can cause burning to the delicate tissued of the gills and fins. It can cause death and it can cause fin rot.

I would get my water parameters back in check before adding anything like salt or meds as getting on top of ammonia can take a lot of water changes so easy to really mess up dosages.

Once that is staying low you can work on meds to help the fish through. But treat for things you can see don't just throw everything at it.

 

[MrWestCoast]

You can get solar air pumps on amazon for around $25 if you have a window near the aquarium that gets direct sunlight. You can also get rechargeable air pumps for a bit cheaper. Some of these pumps can work continuously for 12-18 hours or 24+ hours in intermittent mode. Maybe you can get one of those solar power banks with USB connection and charge the air pumps off it during the day. Most of these rechargeable air pumps have a USB-C port.

[EVoyager31]

On 12/8/2022 at 2:47 PM, Annie said:

All of a sudden all my fish are dying. Just when I thought it was stable and doing great. 
the power went out one night for probably For only a few hours. That’s when I noticed the first couple fish died after that day. It started with an Otto. Then my clown pleco. 
I added some conditioned water and some aquarium salt that is supposed to be beneficial to sick fish. Next day more fish die. A couple days later I do another water change with more aquarium salt thinking this will help before I do the change I checked the levels and The ammonia was slightly high. How did that happen when I thought my tank had already been cycled. For years now.

yesterday I removed the filter and added the tablets for ick treatment. More dead fish. This morning I added two more tablets. It’s so sad to see them struggling and I’m trying to save my Coreys and tetras now and one silver tip left. 
Another thing that might be the issue is I’ve seen that scented candles can affect them and I also bought new incense that is resin-based is this an issue is this what is killing them? My plants were looking great and my fish were looking great and now all of a sudden everything‘s going downhill😢

what to do?

please help, Annie 

My roommate who thinks she’s knows everything is convinced it’s the salt . even though I added that after the first 2 deaths 

I had a similar thing happen when I had bosemani rainbows... very sudden with no clear reason just one after the other. To this day I am not sure what went wrong. So sorry this is happening! Very stressful and disheartening. 

[Guppysnail]

On 12/8/2022 at 3:45 PM, Schuyler said:

My guess is that they were stressed out by something and the power outage changed the temp and lowered O2 levels enough to be too much for some fish.

I’m so sorry you are having these losses. I agree with this. I’ve lost power many times to no ill affect on my fish. These fish most likely are dealing with an ongoing stressor that had not shown up as symptoms or visible behavior changes. Could have been water quality, underlying illness. Most fish illness never show symptoms. Fish are designed to fend off many things and live their lives with them or parasites. I can’t tell you how many times we have gone fishing and cut them for the meat to find huge nematodes living in them. 
The reduced oxygen and possible wobble in parameters could have been the stress factor that put their immune system into a weakened state enough for them to lose tge battle against poor water or illness. 
If the power outage alone was the cause they would have all perished quickly and not in slow succession days after the outage. 
edit to add are you actually seeing ich or just adding meds. Meds are stressful to fish so if it is a stress issue you could be adding to it with the meds  if you do not actually see ich I would not be medicating 

Edited December 16, 2022 by Guppysnail

[Guppysnail]

On 12/14/2022 at 7:40 PM, Annie said:

something that can operate the filter, air stone ,and heater and lights.

I have 2 fish rooms. Hubby gifted me with a generator large enough to operate them. 
They make small gas powered generators. For me and my sanity it was worth the investment 

[rockfisher]

I resently lost power for two weeks during hurricane Ian. I did have power a few hours a day due to a neighbors generator. I have 18 tanks and no all could be powered. I lost a few fish but not many. The tanks with lots of plants did the best. I also cut food back to reduce nitrates. Tanks with more substrate did better than those with less or none. I think this is because the bacteria that remove nitrate avoid oxygen-rich environments. Meaning that the substrate harbored most of the bacteria. I am leaning to the nitrogen as a major factor in the fish deaths. Once it reaches a tipping point deaths can happen very fast. Even a cycled tank that is close balanced only needs a small change to throw things off.  I’m very sorry about the deaths. I hope you keep at things 

[Chick-In-Of-TheSea]

On 12/8/2022 at 2:47 PM, Annie said:

I added some conditioned water and some aquarium salt that is supposed to be beneficial to sick fish. Next day more fish die. A couple days later I do another water change with more aquarium salt thinking this will help before I do the change I checked the levels and The ammonia was slightly high. How did that happen when I thought my tank had already been cycled. For years now.

Welcome to the forum!  Using salt will slow your beneficial bacteria causing the ammonia spike. The bacteria will spring back but it will take time.  Be sure to use a dechlorinator w/ the ammonia detoxifying feature if you intend to keep the salt level as-is in the tank.  @modified lung might be able to explain better how the salt affects the bacteria.  The way I understand it is, the more salt you add at once, the longer it takes the bacteria to recover.  But they will.  (Ammonia also could have been caused by dead fish in the water as @MattyM previously suggested)

On 12/8/2022 at 2:47 PM, Annie said:

the power went out one night for probably For only a few hours. That’s when I noticed the first couple fish died after that day. It started with an Otto. Then my clown pleco. 

I suspect these first few fish died due to lack of oxygen in the water during the power outage, compromising their immune system. 

I suspect the next fish died due to ammonia which occurred as a result of the slowed bacteria, or if not the ammonia, just the after effects of the power outage stress.

Edited December 16, 2022 by Chick-In-Of-TheSea

[Chick-In-Of-TheSea]

On 12/14/2022 at 7:40 PM, Annie said:

I’m am now looking into a battery operated back up system for when this happens again.. something that can operate the filter, air stone ,and heater and lights. Are there any suggestions? I’m doing a search on Amazon right now.

I have a wonderful suggestion, and it's cheap too. It's the Aquarium Co Op nano airpump which only uses a half volt and it has a usb plug that can plug into a 20000 mAh power bank (like you'd use for electronics such as a smartphone).  I got 52 hours runtime out of this simple setup during the hurricane.

Edited December 16, 2022 by Chick-In-Of-TheSea

[Schuyler]

On 12/16/2022 at 7:27 AM, Chick-In-Of-TheSea said:

I got 52 hours runtime out of this simple setup during the hurricane.

That's impressive. I expected it to run for like 8 hours.

There's also a low tech solution that was suggested in a local aquarium group was to put a blanket over the tank to keep as much warmth in and then occasionally syphon off a bucket of water and pour it back into the tank to give some aeration.

[modified lung]

On 12/16/2022 at 7:20 AM, Chick-In-Of-TheSea said:

The way I understand it is, the more salt you add at once, the longer it takes the bacteria to recover.

That's basically it. If your bacteria colony has been establish for a long time, I would expect them to fully recover in 3 days give or take.  If your bacteria were deprived of oxygen, they might take longer. But they should come back for sure.

[modified lung]

On 12/8/2022 at 11:47 AM, Annie said:

My roommate who thinks she’s knows everything is convinced it’s the salt . even though I added that after the first 2 deaths 

Unless you added a ridiculous amount, it's very unlikely the salt killed your fish. Adding salt is almost always a good move.

If your NH3/NH4+ is only reading 0.25 ppm, I wouldn't worry about it too much unless it goes above that.

[Annie]

Thanks to all for your suggestions. 
im still trying to ‘stabilize my tank. 
last night I tested the water

ph-6, ammonia 0-.25, nitrite 0 nitrate 20-30

then I did 25% water change, cleaned algae off decor and sides, 

also added more of my sand substrate that I rinsed well first.

have gotten rid of the dying plants and no dead fish hiding. 
added new red root floaters.

this morning tested again.

ph-6, ammonia 0👍🏽, nitrite 0, nitrate 5-10.

my concern is the ph is pretty low. Should I add a couple sand dollars to the tank ?

My Cory’s fins are bad but I was still waiting on the meds. To see how water changes went…

I definitely need a whole new clean up crew!

I appreciate you guys’ experience and getting back to me, Annie 

another thing. Temp is around 80

and I do have airstone

[Schuyler]

On 12/29/2022 at 9:11 AM, Annie said:

my concern is the ph is pretty low. Should I add a couple sand dollars to the tank ?

What are the GH and KH?

[Annie]

I don’t have a test for those so I don’t know.

[Schuyler]

On 12/29/2022 at 10:05 AM, Annie said:

I don’t have a test for those so I don’t know.

Are you testing the ammonia/nitrites with the liquid test kit or some kind of strip? If it's a strip it may just call this something else

[nabokovfan87]

On 12/14/2022 at 4:40 PM, Annie said:

One more thing is the one bronze Cory that made it looks like his tail fin being chewed up?? 
Annie 

Very likely ammonia burn.  You'll want to check water, complete water changes (don't do a massive one) over the next few days to help clean up parameters.  In terms of the fish, you'll want to treat with aquarium salt and/or bacterial meds to prevent tail rot from settling in.

On 12/29/2022 at 9:11 AM, Annie said:

another thing. Temp is around 80

This is extremely high for corydoras.

On 12/29/2022 at 9:11 AM, Annie said:

ph-6, ammonia 0👍🏽, nitrite 0, nitrate 5-10.

my concern is the ph is pretty low. Should I add a couple sand dollars to the tank ?

You'll want to add in crushed coral or aragonite sand.  1 lb per 10 gallons.  You can also look into something like alkalinity buffers

There seems to be a LOT going on here so let's start from the beginning.....

Please provide details on what species of fish are in the tank, tank setup, photos, etc.

Please also provide what you're seeing on the corydoras.  As mentioned earlier, you started treading for ich.  Why?

Let's take a breath and let's figure things out so you can progress forward with quality information for your specific scenario.