300 gallon tank die off

[Bbentler]

I just was posting because sometime between Friday at 9pm and Saturday at 7pm my entire tank was killed of. I had a 300 gallon fully stocked tank with a dog-faced puffer, several tangs, and school of chromis's, and a beautiful full grown emperor angelfish. My friend called me during the snowstorm while she was checking on the tank and said that everything was dead. The power was out, but the temperature was at 74 degrees, which shouldn't be cold enough to kill everyone. I thought it might be electrical shock, but when my friend fliped the power back on, the GFI didn't trip. Everything died, except a few chormises according to my friend ( I am currently out of town). I did have a small cowfish in the tank as well, so maybe it was the neurotoxin they emit? Could it have been an amonnia spike that killed everything so fast? I guess I'm posting this because I want to know why. I was very fond of my puffer especially and will miss him a lot so I just would like to know why because I am very deep in the hobby but am at a place where if I don't understand this I just might quit altogether. Any help or thoughts on this would help me right now.

Two things to note is that I take incredible care of my tanks and their water quality (tested daily), and I feed my fish at least 30 different foods in order to insure their health. I just wish I could understand why.

Hobby Experience:

 

[ThomasinKind]

How long was the power out?

I'm not sure I can help answer much, but my first thoughts (from all my reading and from hearing other stories) would be either the cowfish or oxygen. I think it would take a while for oxygen levels to drop to a level that would kill everything off. How heavily stocked was the tank? How well did you train your friend w/feeding and general upkeep of the tank while you were out of town?

Years ago I lost almost an entire tank when I ended up in the hospital and my parents overfed everything for about 6 days (huge ammonia spike).

Sorry to hear about your loss

 

[NewKid630]

Lack of O2 is my guess. With no power the skimmer which was providing most of the O2 obviously stopped. Happened to me over night a few weeks ago. So now I have an airpump on battery backup when needed.

 

[DamnPepShrimp]

Bbentler sorry about your lost. I too am curious as to what happened. I do not want this to happen to my tank, or anyone's tank. Lack of O2 could be a possibility. Newkid630, you just have an air pump set up on battery that turns on when the power goes out? Can you buy this set up somewhere? More details please! I want to make sure this doesn't happen to my fish, I am getting very into the hobby and expenses, can't afford to lose anything!

 

[gotoneon]

The tank does not sound over stocked, and from my experience with my 300 gallon tank the power would have to be off for 24 hours before you would be worried about lack of O2. The tangs and angel do use lots of O2 due to their nature of being large and very active. I also do not think it was the temp, or amonia from just the power being out. I moved 14 hours with all my fish in a 55 gallon cooler. At the time there where a bambo, miniatus, naso, and lion, all mature sized. I only had air going to the cooler and the temp troped about four degrees but no heath problems. My guess it the cowfish let off it's toxins due to stress which killed a couple of the weeker fish or inverts in the tank, which jacked your amonia and nitrates, which kill a few more fish and inverts which raised your amonia and nitrates even more, and so on. With out good circulation and oxygen it is amazing how poluted a tank can become from just a few little critters dieing. Very sorry to hear about your tank but it sounds like you are a great care taker for your fish. Responsible tank keepers are valuable so I hope you get your tank up and running again.

 

[shanevrr]

i think it was lack of O2, happend to me within 6 hours.

 

[NewKid630]

Tank temp is also important to know. Mine are at 78-80. higher temps = less O2 usually

And yeah the airpump is on a standard UPS. I am looking for something cheap that will turn on when the power is out, but for now it's just on all the time.

 

[Bbentler]

What does UPS stand for?

 

[treejohnny]

Uninteruped Power Supply......it is like a battery back up for a computer used to run vital part of aquaruim like air pump or powerhead in display tank.

 

[BTTRFLYGRL]

My guess would be lack of oxygen combined with the death of the Cowfish...though I'm not sure how the smaller Chromis would have survived the toxins from the Cowfish

Sorry for your loss.

 

[Bbentler]

I've come to the conclusion now that I am home and see the damage, that it had to have been an oxygen issue. Since my friend found the problem last night and got a pump running, I found my favorite fish had "come back to life." It seems that oxygen was being used up quickly once the power went out since I had a large full grown emperor and a large vladming tang. I am going to miss my emperor so much too, cause she was very kind and gentle to all the fish. Luckily my puffer survived so I will have my little puppy to play with. Thank you all for the information. Needless to say I am going to setup a UPS backup system immediately so I will never a lose a fish from something like this ever again.

 

[fantastic4]

dbl post

 

[fantastic4]

did your friend clean the outside of the tank with bleach? If bleach managed to get in the tank via sump or canopy, you risk losing an entire tank.

example... while cleaning... dipping fake coral or fake plant in bleach mixture and the forgetting to rinse the bleach off can kill a 200 gallon tank in an hour.