Introducing Fish Into Tank With Co2?

[Tigermoth]

I started using diy co2 in my 4" tank a few months ago. Plants are doing really well and all the fish have been fine. The only new fish I've introduced since the co2 was a few peppered corries a few days ago. When I let them out of the bag (after a 30 min float and a couple of dunks to introduce a bit of tank water to the bag), they all started gasping at the top, then swimming upside down and doing strange things like lying on the sand upside down. After a few hours they sorted themselves out and were fine.

The only thing I could think of that caused this was having the co2 system and the possible shock of the lower pH. Does that make sense? What is the correct procedure for introducing new fish when using co2. My LFS I'm sure has very similar water parameters to me, and this has never happened before, coincidence I wonder? I keep the tank understocked and well maintained, with weekly partial water changes.

 

[blue acara]

I think the co2 probably did give them a shock, especially if it was at 30 ppm. When I add fish to my planted tank I have the lights off and an air pump going.

 

[Tigermoth]

Thanks ba, yes I always have the lights off, in fact I have to take the hood off to be able to float the bags.

 

[Tigermoth]

Just out of interest, approximately how long will it take for all the co2 to be driven off and the pH to return to its normal level if I use an airstone and remove the co2 diffuser?

 

[Tigermoth]

Does anyone know approximately how long will it take for all the co2 to be driven off for the pH to return to its normal level if I use a smallish air pump and airstone, and also remove the co2 diffuser?

 

[Tigermoth]

bumpity-bump-bump

 

[blue acara]

2 hours and most of it will be gone. I put an air pump on at night in my tank for 3 30 min intervals (as I have a reasonably high fish load) and the co2 is mabie 10 ppm in the morning.

 

[Tigermoth]

Thanks ba, that's good to know.