2 Fish dead in 3days OMG

[bandit]

Ok so I purchased a small Yellow tang on Friday he was eating and very healthy in my tank, seemed very happy all night slept next to my copperband. The power went out that night for 4hrs I had a battery pump running but no heater. Tank dropped from 78.5deg to 73deg over night. In the morning the yellow tang was nowhere to be found checked everywhere and nothing.

I figure he died in a rock and the critters got him, now last night I come home to find my copperband dead who I have had for months. He had no sign of disease, but had been breathing heavier sense satarday.

Could the temperature drop have killed these fish?
I havent checked PH only cause need a new kit and its always been fine? and if it was water quality would i be losing SPS and cleaner shrimp?
I did spend alot of time in the tank on Sunday looking for the yellow tang body and moving corals around.


Tank is at least 10plus yrs running 65gl with 30gl sump and 100lbs live rock.
Livestock:
-yellow watchmen/and shrimp
-2 clowns
-2cleaner shrimp
-lots of hermits/snails
and sps, and softies som ehard to keep sps which are doing great.

[Greatwhite]

Yellow tangs are very sensitive fish - especially on moving day and the first few days after.  If you just added him Friday, and he died, he may have just been "unwell" from the start and the temperature drop may have pushed him over the edge.

How long did you have the copperband?  I know tangs are territorial, and I think copperbands can be shy and stress easily when kept with stress-inducing fish (like tangs can be).

I went away once for a week in the winter with the furnace turned right down -- and my heater was off in my tank.... and everything survived just fine.

[Hookup]

could be an oxygen related issue.  power goes out, flow stops (surface turbualnce goes down)  o2 levels drop... heavy breathing... dead fish...   grasping at straws though... not sure

[bandit]

I had the copperband for months, and he was about 3times the size of the tang.

Maybe the battery pump wasnt enough? I cant wait untill we get our whole home generator. 

[Greatwhite]

I can't imagine oxygen would have been depleted enough to kill anything in 4hrs, but stranger things could happen, I guess.

You might want to test your water, just in case.  There might be something "off" that was only made worse by less flow.... maybe?  it's a good idea to test anyways.

[JetJumper]

Corals will eat up oxygen levels in the water and fast.  then they close up until it is viable for them to use it again.  If the corals in the tank used all the oxygen levels this could have caused harm to the fish.  I don't have a statistical number on how much corals use.. but its an option for sure.

[bandit]

Corals will eat up oxygen levels in the water and fast.  then they close up until it is viable for them to use it again.  If the corals in the tank used all the oxygen levels this could have caused harm to the fish.  I don't have a statistical number on how much corals use.. but its an option for sure.

this make sense my yellow leather and toadstool has been closed up sense and is just starting to open up again.

[Greatwhite]

... your corals could also be closed up because of toxicity in the water... it's better to be safe than sorry - test it.

(I'm not disagreeing that oxygen levels may be part of the problem, but it's best not to focus on the "least disastrous" possibility, and hope that everything bounces back on its own...)

[Hookup]

Do you have a skimmer?  And a sump?  If so, likely oxygen was ok after four hrs. I should have added that above.  But if surface disturbance is the only way gas exchange is happening on your system I'll hold my bets on oxygen depletion. It's adding up.   Where was the bacteria bloom that often occurs after big fish die in closed systems.  Of course maybe the deseased was removed within the first 12 hours or so.

[bandit]

No bacteria bloom what so ever. I have a 30 gallon sump I assume its a 3'x18"x18" rubber made 3/4full. My skimmer has been off for 1month because my impeller broke and im waiting for a new one.

So basically all Im getting for oxygen is surface movement.

[Hookup]

the falling water to the sump does add oxygen, assuming it's open top/exposed... many people cover their systems to help reduce evaporation... but that can lead to poor gas exchange issues...

i'm now more than ever convinced you've had an oxygen poor system that was pushed over the edge when your power heads when out...

[bandit]

im leaning that way checked ph and  inconclusive



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[bt]

I'd put that 8.1-ish.

[JetJumper]

Photoshop colour matching agrees at 8.1ish

[bandit]

ok great thanks for the help, so I just added 2 power heads to my sump pointed at the surface and cleaned my korila's and wow I guess they where real dirty beacause my flow is 10 times what it was before. The new pump for my skimmer is on order also