Sudden Fish death issue

droth335

New member
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 BTA's were shrunken but not completely withdrawn.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.

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.
 
Stray voltage? Biological or chemical contamination? Temperature spike? Poisoned somehow? I so sorry for the loss. When. Fish get that size and have the obvious personalities they do it is a true tradgedy. Just like humans though, we all just hope it was fairly quickly and they did not suffer.

Sent from my SM-G930V using Tapatalk
 
Thanks for the ideas and condolences - the Naso has been my wife's favorite fish for the past 3 years.

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). That's the worst part - just not having any idea what caused it.
 
That sucks. Larger fish dying first suggests oxygen deprivation. Do you have anything that can become toxic? Caulerpa? Slugs? Etc
 
Pretty sure a sea cuke got caught in skimmer pump and caused the issue. Pump stopped running and I extracted a bunch of plasticy type tissue from the impeller. Not sure how he made it there but cant find him elsewhere so that is our prime suspect ATM.
 
I had the same thing happen to my tank a few weeks ago, pink/black cucumber was ripped apart in a powerhead. I lost 7 fish, 4 survivors but all my corals and inverts were fine. I did a large water change and put in fresh carbon. The poison leaves the system pretty quick so everything that survived should be ok!
 
Wow sorry for your loss. Always wanted to get one but after reading this I think ill have to pass.
 
I did 115 gallons of water change yesterday (55 + 60) and added ~5lbs of carbon. Lost 20+ fish. It appears only survivors are 2 clowns and mandarin.
 
I did 115 gallons of water change yesterday (55 + 60) and added ~5lbs of carbon. Lost 20+ fish. It appears only survivors are 2 clowns and mandarin.

Did the BTA's make it? Man I would be so mad right now. Good luck moving forward
 
Thanks for the condolences. BTAs and ritteri seem fine. Coral and most inverts do as well although a couple of hitchhiker crabs died.
 
Back
Top