need help

[nicfo25]

I had this posted in reef disscusscion and didnt get much feedback, so I am going to try here.

Thanks in advance everyone!

Ok so my fish got ich in my display tank. I removed them and put them in a 38 gal QT tank. I lowered the SG to 1.009 within 3 days. Everything was going good, 4 weeks at 1.009 and then came time to raise it back up. Last night I raised the SG to 1.13. This morning I fed them and everyone of them looked good and ate good. I got home this afternoon and they are all dead except one which is at the surface gasping for air. I dont know what the heck happened.

No ammonia No nitrite and plenty of water movement on the surface. Temperature is fine, filter is running fine.... I dont get it. The only thing I noticed was the water was a little cloudy but not too bad. What do you guys think. QT tank has been running for 5 months.

I measured SG with a calibrated refractometer.
My next question is what do I do with the tank from here on out to make sure it is ok.

Update - 1 survivor green clown goby

[DustinB]

After all the stress of being in low salinity I would guess the swing killed them. How did you adjust the salinity? Usually you should just start using saltwater slowly as your topoff water instead of RO for topoff.

[Sk8r]

Gasping for air would indicate a possible oxygenation problem, and here it gets into chemistry. A rise in salinity or temperature decreases the oxygen-carrying capacity of water. Possibly they were marginally ok at the old 1.009, and when it came up, the oxygenation proved inadequate. That would be my guess, offhand. I am so sorry---to go that long successfully and then to lose them to this technical glitch is very hard, but that's what I think may have happened.

[bnumair]

what kinda equipment r u using on the QT tank. gasping for air and sudden death could mean 2 things, low oxygen or hydrogen sulphide poisening. r u using a denitrator or any equipment where water passes real real slow?

[Sugar Magnolia]

Gasping for air would indicate a possible oxygenation problem, and here it gets into chemistry. A rise in salinity or temperature decreases the oxygen-carrying capacity of water. Possibly they were marginally ok at the old 1.009, and when it came up, the oxygenation proved inadequate. That would be my guess, offhand. I am so sorry---to go that long successfully and then to lose them to this technical glitch is very hard, but that's what I think may have happened.

This would be my guess as well. You raised the salinity too quickly. :( Sorry for your losses.

[nicfo25]

I raised the SG by doing a 5 gallon water change. It raised it by .004, I was under the impression that this was not to fast. I have performed it faster than this before with no ill effects. I have a oversized canister filter directed at the water surface plus a powerhead directed towards the surface. Alot of surface movement... How could this not be enough to oxygenate the water??? I am stumped

The one fish that survived is doing fine and eating. I am not sure how to move forward after this. I will perform a 50% water change tonight. What would you guys do before trying to add another fish??

Oh and no denitrater just filter, heater and powerhead.

Thanks Guys

[nicfo25]

Also the weird thing is that it took almost 18 hours for this to happen. 12 hours after the waterchange, the fish were fine and ate great. A couple hours later barely living.

[nicfo25]

anyone else have any ideas???

[nicfo25]

bump

[funkejj]

How many and what kind of fish did you move to the QT tank? What were the water parameters of the QT Tank? And as Sk8r said as well as others Gasping for air would indicate a possible oxygenation problem. Even though you thought you had enough water flow maybe you didn't.

[Skeptic_07]

you said the water was a little cloudy that could be a bacterial bloom which can cause low oxygen. its likely to happen too because your QT probably had 0 bio filter when you moved them. its weird that it would happen after 4 weeks though, maybe it was increased feeding. that combined with higher sg or a temperature spike.. or all three occurring at the same time definitely could have suffocated your fish. sorry for your loss, i know how it feels.