[dogdoc]

Alright, this is kinda weird. I bought 5 koi angels from a reputable breeder on Aquabid. They made the trip well and were placed in my 10g quarantine tank for two weeks. They all did well and were eating/acting normal sometimes a little shy, but otherwise ok.

So last week, they all made the trip downstairs to my 75g planted tank which is to be their permanent home. Two days later, as I was headed out in the early a.m. I noticed one of them stuck to the side of my Koralia and I thought, dang, I lost one. When I came back an hour later, I decided to fish out the "body". I unplugged the pump and the fish swam weakly away. I managed to net it and moved it back to the QT to await the inevitble. Well, a week passed, and the fish did well. Ate/behaved normally. So today at noon, after a big water change in the main tank, I moved it back. As I'm looking at the tank, I notice the same problem fish laying on its side on the substrate. Again, weak, but alive. Again I moved it back to qt.

So I'm confused. Why does this fish do alright in qt, but have near death experiences in the main tank. The only difference I can think of is the CO2 injection in the main tank. I thought maybe that was the culprit the first time, but today it happened mid-day with lights on and plants pearling. All the other fish seem fine, including the other four angels from the same shipment.

 

[dogdoc]

It just seems really weird that it does fine in the QT, and goes down so quickly in the big tank.

And yep, all the others are doing great.

My wife says it's because it's the only one with a name so far.

 

[dogdoc]

That is exactly what I did. Changed about 70% of water, then moved the fish. So the CO2 was low when transferred.

 

[dogdoc]

Well, the CO2 was the first thing that came to mind for me. Essentially it is the only difference between the two tanks.

The part I'm having trouble understanding is why only one of the 5 fish is having trouble with it. I've introduced other fish the same way too. Rummy noses, bolivian rams and others. None have seemed to have issues with it. At least no more stress than would be expected with the move.

 

[dogdoc]

Of course it had to be the best looking of the bunch as far as color/markings. And the darn thing is looking at me from the quarantine tank like "who me?" I was really hoping that it would pair up with one of the others.

I guess all I can do right now is give her/him a while in the qt and try again at some later time. Maybe when it is a little bigger, things will go better.

 

[dogdoc]

I think it has to be the CO2. I just tried moving 5 rummys out of the qt and into the main tank and ended up fishing all of them back out. They looked like they essentially "passed out" floating upside down or being blown around by the water movement. After a minute or two back in the qt, they all came around like nothing was ever wrong.

So this brings up another interesting theory. Fish must be able to build up a tolerance to CO2 in the water column. None of the rummys that are in the main tank, nor any of the other fish look stressed, but man did it do a number on the new guys. My drop checker is usually yellow, but since none of the fish seemed to mind, I haven't been worried about it. I'm going to back down on my CO2 and shoot for "green" for a while.

So the one angel that had issues must be somewhat more sensitive than the others.

Thanks for all the help.

 

[dogdoc]

Kind of an interesting footnote here. I turned down the CO2 from bright yellow to green on the DC. The other angels seemed to appreciate that. They are more active and outgoing now. Everyone seems happy.

Except that same fish. I have tried to re-introduce it into the tank with the CO2 turned down and it does the same thing. Acts like it is dying. I had to scoop her out once again. Just weird.