Sudden fish deaths

[DRoth335]

Fed both tanks last night a 9:40pm and everything was fine. Came home from church this am and the 300 looked slightly cloudy so I walked up to it and discovered most fish were dead or dying. The ritteri was curled up quite a bit and clearly not happy. BTA's were shrunken but not completely withdrawn. Some inverts seem fine but a couple of red hitchhiker crabs were dead. Snails seem affected but not dead. Elegance and frog spawn very shrunken. SPS seem ok color-wise but not much PE.

We have a ground probe in the tank so I don't think stray voltage. Temp has been consistent at 78 degrees. Can't rule out biological or chemical contamination but also can't determine a source. I was gone most of yesterday so didn't even have my hands in the tank which is the only source of introduction I can think of and I am very careful around the tanks (and the other tank serves as a control group and is fine today).

Biggest issue is, I can't figure out what is wrong. Parameters are:

- Alk 9.3
- CA 480
- Mag - 1300-ish
- PH - 8.0
- Nitrates < 5

We dose CA, MG, vinegar and all reservoir levels look right so it doesn't see as if the doser freaked out. I feed both tanks the same food at same time and other tank is fine so food doesn't seem to be an issue.

The purple tang was one of the last to succumb but he seemed fine when I got home except he was gradually losing color in his dorsal fine. He died about an hour after discovering it.

About 7 fish are still alive - mostly smaller ones - 3 bangaii's, 2 clowns mandarin (although he looks quite sluggish so might not make it.
Dead: 11" male naso, 7" PBT, 6" gold spot rabbit, 6 lyertail anthias, 1 cardinal, and I'm sure I'm missing some. A couple of wrasses are MIA but I suspect dead in rocks.

I just finished a 55 gallon water change and have 75 gallons more mixing so will do another one and RODI is running so I can do another change late tonight.

Any idea what might cause this? A friend suggested bacterial bloom which might have created oxygen deprivation but PH is fine so that seems odd.

I have not changed anything, have not had any kids visit that might have "spiked" the tank with something.

Any ideas or hypothesis to check into would be welcome. At a complete loss as to what it might be. TIA.

 

[AcroNem]

Test for ammonia and nitrite, this sounds like a crash of some kind. Or something fouled the system.

 

[Humblefish]

Sounds like a toxin of some kind got into the water - household cleaner, bug spray, even a scented candle immediately come to mind.

Any chance a nem got stuck inside a powerhead or fish have been dying behind the rocks for days before? Or do you have a sea apple (or another toxic animal) in your tank?

Test for ammonia ASAP, start running carbon and let's call on the #reefsquad for more input.

 

[Humblefish]

If ammonia comes back positive, dose a reducer immediately (exs. Prime, Amquel) to get that under control until more water is ready for a water change.

 

[Diesel]

DANG!!
This is the worst nightmare we all can come home too for the tank.
Knowing what you did is all perfect but you can't explain how fast it all goes.
I agree with a toxin in some sort as it went super fast.
Any chance you have your skimmer airline pulling air from the outside?
Did you ran the heater in your house or a fan?
Was there anybody in the house while you were out most of the day yesterday?

 

[Brew12]

I'm very sorry for your losses. Sounds like you lost some amazing fish.

We have a ground probe in the tank so I don't think stray voltage.

If you have a volt meter I would unplug the ground probe and test voltage from the tank to ground. That would rule out a failed electrical component. If your system is on a GFCI, then there is no need to do this.

A friend suggested bacterial bloom which might have created oxygen deprivation but PH is fine so that seems odd.

A bacterial bloom can cause O2 deprivation without impact pH significantly. pH is only impacted by CO2, not oxygen. If the bacteria are consuming the O2 but not changing the CO2 content significantly because of your gas exchange, this is possible. I would almost expect your pH to rise a little during a bacteria bloom.

 

[melypr1985]

Bacterial bloom or toxin... either way test for ammonia right away. Run fresh carbon and do the water changes you have planned. I'm so very sorry about your losses.

 

[DRoth335]

Test for ammonia and nitrite, this sounds like a crash of some kind. Or something fouled the system.

Both are undetectable (salifert) - this was done after the 55 gallon water change

 

[Maritimer]

If you've got fish you can't find, and suspect them to be dead (which seems reasonable, given what you came home to ... so very sorry that you have such a nightmare to deal with!) an ammonia reducer might not be out of order regardless.

I wish I had more to offer - thankful you've gotten great advice from several sources!

~Bruce

 

[Broadfield]

Do you happen to use a tank controller that would maybe show a spike in pH, temp etc? I'm not sure how long it takes for pH to stabilize after a huge fluctuation though... probably a bit in a 300.

 

[ReeferMaddness843]

Sorry to hear about the losses and lack of evidence pointing to a specific issue. Have to be the most frustrating situations. Won't be able to be much help myself, just want to express my condolences. Best wishes in a solution and rebuilding!

 

[DRoth335]

I'm very sorry for your losses. Sounds like you lost some amazing fish.

If you have a volt meter I would unplug the ground probe and test voltage from the tank to ground. That would rule out a failed electrical component. If your system is on a GFCI, then there is no need to do this.


A bacterial bloom can cause O2 deprivation without impact pH significantly. pH is only impacted by CO2, not oxygen. If the bacteria are consuming the O2 but not changing the CO2 content significantly because of your gas exchange, this is possible. I would almost expect your pH to rise a little during a bacteria bloom.

I do not have a volt meter. O2 deprivation seems to be a likely culprit based upon ruling out many other thing. Clearly something I am unable to test for.

I changed carbon 3 days ago but added more today. I just completed a 60 gallon water change and will do another 60 when the RODI gets enough water made.

 

[DRoth335]

Do you happen to use a tank controller that would maybe show a spike in pH, temp etc? I'm not sure how long it takes for pH to stabilize after a huge fluctuation though... probably a bit in a 300.

Unfortunately, I do not have a controller.

 

[DRoth335]

Sorry to hear about the losses and lack of evidence pointing to a specific issue. Have to be the most frustrating situations. Won't be able to be much help myself, just want to express my condolences. Best wishes in a solution and rebuilding!

Thanks. I hope the coral & nems all stay ok.

 

[DRoth335]

DANG!!
This is the worst nightmare we all can come home too for the tank.
Knowing what you did is all perfect but you can't explain how fast it all goes.
I agree with a toxin in some sort as it went super fast.
Any chance you have your skimmer airline pulling air from the outside?
Did you ran the heater in your house or a fan?
Was there anybody in the house while you were out most of the day yesterday?

No outside air for the skimmer. Our furnace has been running the same as normal for this time of year and no one was home yesterday (we are empty nesters and my wife was gone too but she is also very knowledgeable about the tanks). I remain stumped on a definitive cause.

 

[Brew12]

No outside air for the skimmer. Our furnace has been running the same as normal for this time of year and no one was home yesterday (we are empty nesters and my wife was gone too but she is also very knowledgeable about the tanks). I remain stumped on a definitive cause.

Seeing as you have 2 tanks I would doubt that it was an issue with outside air. I would think that would show in both systems.

 

[DRoth335]

My wife just remembered we had a sea cucumber in the tank (rarely see him) and our skimmer pump just quit working in the past hour. I extracted this stuff in pic from it. It is very tough, almost plasticy. Could this be the remains of sea cuke and could that cause the toxin?

 

[Humblefish]

A sea cucumber will normally only release it's defensive chemicals if it feels severely threatened.

Getting sucked up by a pump intake, or being damaged on it's way into an overflow will sometimes trigger it.

 

[melypr1985]

Didn't @redfishbluefish just have this happen?

 

[redfishbluefish]

Yes....best I can tell the red and black cucumber got caught up in an MP40 and than puked it's guts killing four fish. Found the remains of the cucumber stuck on the outside of the MP40. I also think the reason he was up next to the powerhead was that I had recently picked up a diamond goby that clean up all the cucumber's food, and he was just looking for food. I had had that cucumber for years.