300 Gallon Tank Crash - All dead less than 48 hrs

[hizbaby]

have a 300 gallon at office, everyone was fine at 6pm firday, sunday by 4pm, all but one fish dead! this is my boss's tank, it is well established, he has had most fish in it for over ten years... over $2k in loss. At a loss as to why ... is it possible the temp got too cold? there are no heaters on tank, never has been, the outsige temps never went below 55 for either nite, could 300 gallons go too cold that fast? Or could there be another issue? the tank has been there for years ... feel awful !! Please advise! ... apparently one fish survived, but lost 2 clarkie clowns, htppo fang, emperor angel, clown tfigger, yellow tang, black trigger, queen coris wrasse ... will get more details when get to work .... dont wanna go, itz gonna be so painful to see everyone gone ... should note, temps IN office not below probly 68 at very lowest, and hard to imagine even that low, days have been in the 70's ..

 

[lilgrounchuck]

It’d take awhile for 300 gallons to cool down to 55 from 78-80. Overnight inside a building if the building is closed and insulation isn’t going to do it. Maybe an exposed wire on equipment leading to stray voltage in the tank?

 

[Ultra Aquatics]

Were any new fish added recently?

 

[Pete Luna]

What's temp in Office? Would not think it is the cold something else caused it. I would look for an outside source of contamination, (cleaning person) or pest control

 

[frankiereef]

Is the tank have Apex Neptune System? you can track the data to see the possible answer.

 

[Phillthy]

Was this tank well kept? Someone doing water changes and maintenance? Checking parameters? Need more details to investigate.

 

[F i s h y]

Accidental poisoning by cleaning supplies.... ive seen it happen at the office before?

 

[AnneO]

Someone desinfecting the office because of COVID?

 

[hizbaby]

Ofice temp same as ever, no new additions, no pest control, BUT did have, on Thursday cleaning woman there, she did spray air freshener, but no more than usual, and everything was normal from then until leaving friday at 6 ... he believes they died in the night on saturday, because they were not yet floating from what I understand... NOTHING Different, and I was last one there, feel awful, and can't believe temp was the cause ... I too think HAD to be some other failure, how would one know if it were voltage issue?

 

[dohc97]

Tell us about the setup and we can go from there, a foreign substance or equipment failure would be my guess until we know more

 

[piranhaman00]

Cleaning chemicals contaminated,

 

[hizbaby]

no covid disinfect, just regular cleaning, we have been on no contact, so not even usual volume of traffic into office, auto repair shop. and it were from cleaning person chemicals, which is only fabuloso and like fabreeze air spray, would that not have shown signs by friday since it was done on thirs?
also to clarify, OUTSIDE temps in the 50's, INSIDE temp not likely below 65 at WORST and only for a cple hs in the dead of nite

 

[Leadfooted]

Ugh, I'm with others, leading towards Lysol / cleaning.

 

[Amado]

That’s doesn’t make any sense why would you spend all that money on fish and equipment and not buy a $30 heater.

 

[Leslie Tabor]

I would say we need more tank parameters to make any kind of educated guess. I would get someone in there to test water, check equipment etc. Not jump to blame the cleaning lady. I would ask if she did/used anything out of the ordinary.

 

[JumboShrimp]

I’m inclined to say it wasn’t the temp. What a shame if it was the cleaning lady going heavy / careless on the spray. Emp. Angel. Queen Trigger. Oh my. So sad.

 

[ihavecrabs]

I wonder if the store had a power outage over the weekend and oxygen became depleted.

 

[Pardsie]

I would tend towards oxygenation issue

 

[hizbaby]

im here now, the queen wrasse made it, a blue damsel, and a black ( i think he is a trigger) ... the cleaning lady was here on thurz, so surely we would have noticed something by Friday at close... no power out cuz computers were still on where they were left ... have had power outages b4, for much longer in both hot and cold weather, no issues, ... i too am thinking some kind of fail ... uv sterilizer maybe, as it has been removed... the worst part is i feel he thinks we did something wrong ... have been caring for this as well as hiz home tank for 2+ months straight while he was gone, and have also cared for it for shorter times for 3 years ... he is who started us on our own home Reef Hobby, been there every step of the way for us.... he is so distraught he cant even speak, all we got from him was that tank temp killed fish .... which is just too hard to accept as EVERYTHING has been the same for so long... although we did not kno there was no heater, but he said has never used one, at the office or in his home tank ... we are morified by the loss ... will try to get more info when I can from him.
total fatalities: emperor angel full grown, clown trigger full grown, 2 clarkie clowns had for many years, hippo tang full grown, black trigger full grown, yellow tang, had many years.
Thank u ALL for your replies and advice ... will post more when kno more ... this is SUCH a AWFUL and puzzling thing....

 

[hizbaby]

yes to upkeep and water change, did one bout 2 weeks ago, as per the normal manner he has always done it in ... tank is so welll established he rarely does any testing other than salinity ... he's been reefing for over 25 years ...