Fish Only Tank Crash....

[Tenner]

Hey all,

A friend of mine has a 185g FO. She had 13 fish, several very large, like two large puffers. Her sump was disconnected from the system Saturday last week. We added a heater, powerhead and six inch bubble wand for some extra oxigenation.

Yesterday, six days after the sump was disconnected at 8am all the fish appeared in good shape. When she came home from work around 5:30 all the fish were dead and laying on the bottom of the tank.

The temp was 80, which is normal for that tank, Amonia was low, the air pump had failed, but the power head was still breaking up the surface tension of the water. All the fish were dead on the bottom of the tank and completely WHITE?

We are looking for how this happened. Is the white color of the fish any indication of what might have happened. by the way she had several hermit crabs that are still alive...

Any help would be appreciated, Kim is heart broken and afraid to keep the tank.

THanks
Matthew

[DragonMorayEels]

I feel terrible for what happen but from what you are saying the tank for one thing was over stock and you did have or had a sump and I would have to guess a skimmer in it. If yes, why did your friend remove these?

With so many fish in the tank and oxygen would have to be the question as well as the fish swimming in their own waste. As well it is understood that 80 F not cause those fish deaths, so it lies in either waste build ups or oxygen levels or both.

As you said, you are looking to see how this might had happen and I have to say your friend started a chain reaction after removing the sump with skimmer.

Im sincerely sorry Kim and also that hermits not need the higher oxygen levels as the fish required being that there were so many, Please, you should think about replacing the sump and skimmer.

Buddy

[Mad Scientist]

Tough one. I would suggest swithing to LR based filtration.

LR is expensive, but so is livestock. Why even bother with the 6" bubble wand, that seems like kind-of a freshwater mentality. If she wants to have LT success keeping big SW fish she needs to have much more robust setup. In most cases that mean LR and a HUGE skimmer. Furthermore, when in doubt, do a bit water change. As soon as the sump was out of the picture I would have done a 25% water and added 3 or 4 big powerheads.

[saltyESQ]

why did you have any amnonia? how long has the tank established?

[DragonMorayEels]

Mad Scientist, Hope I say this right; I never attempted to have so many fish in one large tank for I know that any person attempting to do so would have to make huge water changes once a week and in not knowing the size of all the fish, I have to go with a weekly water change of 40% if not more and the water would have to be freshly made and not that it`s been sitting around for some weeks.

I agree with Mad Scientist on all else for me it be the number of fish and it was mentioned that some were rather large. So only on water changing percentage I have to go much larger and also I base my views on not just how many fish the person have in any tank but also the amount of food that must been dump into the tank and without a skimmer, the only method left would be water changes other then using both.

[Wolverine]

Originally posted by saltyESQ
why did you have any amnonia? how long has the tank established?

Most likely it's from the decay of the 13 newly dead fishes.

I would agree that oxygen would be the top thing on my mind. That many fish with just a powerhead circulating is a set up for disaster. If the air pump had kept working, then it might not have happened. The color doesn't mean much. Many fish turn white/pale when they die.

Why, exactly, did she disconnect the sump?

Dave

[marrone]

It's very possible the fish died from a lack of oxygen but I would have also check the Ph. A big drop in the Ph or a steady drop of it over the week could have killed the fish. Once a couple of fish died than it would have just been a dominino effect as the conditions in the tank would have been pretty bad.

[maroonytunes]

Do you have any test results from before the deaths and sump was disconnected?

[Wolverine]

Originally posted by marrone
It's very possible the fish died from a lack of oxygen but I would have also check the Ph. A big drop in the Ph or a steady drop of it over the week could have killed the fish. Once a couple of fish died than it would have just been a dominino effect as the conditions in the tank would have been pretty bad.

It would have to drop really low to be the cause of death for all these fish that quickly. Even then I would suspect it's related to the oxygenation issue (or carbon dioxide issue, if you prefer to look at it that way).

Dave

[LRS078]

First off...I'm very sorry for her loss. We have some "big puffers" and they are quite like family members. My condolences....

As far as causes...I'll jump on the low O2 saturation/depletion bandwagon. If the tank had been stable/cycled and there were no new additions (hence no new pathogens) then the waste issue for THAT big of a death/crash is harder to believe. Sure there could be some waste but not lethal. If the water truly tested even semi normal we can probably throw that out.

However, I do have to ask....were any of the fish in the tank any species of boxfish? They can upon extreme stress or death voluntarily release ostratoxin which could wipe out a tank fairly easily. Usually you hear about the water being cloudy but not always. If the O2 dropped low enough for the usually somewhat finicky boxfish it could of nuked the tank.

BTW, if you took the sump out what were you using for filtration/skimming/etc?

Going forward, I would take the tank "dry" for at least a month after giving it a good scrubdown. Then set it back up with the ususal cycle/damsels/etc program. Then slowly rebuild the stock list.

Sorry once again...

[Tenner]

Hello all,

Thanks very much for your kind words, Kim read through the thread yesterday. And, yes the fish were like family members to her.

Here is the follow information to many of the questions above.

Overview of the project; System had been up and running for three years.
She had a 185g fish only, plus a 130g reef, two refugiums (60g each) and a sump all plumbed together as one system. Recently some family issues caused her to re-think this setup and down-size significantly to reduce her maintainence schedule. No snide remarks here on the setup, it was a monsterous, crazy setup. The guy that built the entire system had everything housed in a large wood structure with no room to work on anything. Hey had one small skimmer in the sump and some live rock in the sump for filtration. They had very low lighting, mostly T-5's. No corals really ever made it in their tanks. But the fish did well enough.

Two weeks ago we pulled the reef tank out of the system. We moved the reef tank to a 100g with new lighting and filtration, much more stable and low maintainance. Stand alone.

Then we let the overall system (big system) rest for one week. After the rest period we dismantled the two refugiums and the sump. The 185g FO tank was stand alone. Heater, power-head and bubble wand were added directly to the tank. The feeding was reduced about 70% for the next six days.

Then of course the tank crashed. We thought since the air pump had failed perhaps the tank got electricuted but, the air pump seems fine now.

More info:
No box-fish were in the tank. So no apparent poising.

The gravel bottom of this fish only tank had been cleaned a few weeks before we started dismantteling everything, so the tank was pretty clean.

I don't think the fish load was too large for the tank, although removing the two refugiums (60g) each, and the sump had to have some impact. We were scheduled to hook up a new sump with better overall filtration for the tank Saturday the day after everything had died. I thought the tank would last a full seven days with filtration. Obviously I was wrong.

At this point I think the oxigen saturation was the start of the problem, then once one or two the fish died, the cycle of build-up waste turned the tank over quickly.

The only item still unusuall for me was the color of every fish in the tank. White. I've had reef tanks since 1987, and most of the fish that die maintain some color, although they quickly rot. In this case 8-hours and every fish was pure white.

Thanks again for taking the time to respond. I really appreciate it.

Matthew

[BTTRFLYGRL]

My moms heater malfunctioned [got too hot] killing her Damsels, they were completely white...

Sorry about the loss.

[LRS078]

I've heard calerpa can release nitrates/toxins it normally ingests when it gets to its reproductive stage.... If you redid/ripped it all out its possible I suppose that could of contributed but I'll defer to Petstorejunkie on this one as she has a ton of experience with this type of thing....

If the O2 was depleted in the tank perhaps that had something to do with the color, hard to say, there isn't a CSI for fish unfortunately....

[Tenner]

LRS078,

One of the 60g refugiums was chalked full of algae. She had probably the best stock of turtle grass I've ever seen in a closed system.

But, since we simply dismantled all the plumbing before cleaning out the refugiums and sump, there was no release from the alage back into the main tank.

We checked the heater for any apparent cracks for water inside, it looks sound. But there is no telling if it went hay-wire. When she got to the tank it was 80-degrees.


Thanks
Matthew