Converting Tropical to Coldwater

[DemonShark]

I have a 30g lightly planted fry tank. The temp is set at 81F right now.

Today, I am moving the fry out and am converting to coldwater, at 74F.

Will there be any adverse effects on the nitrifying bacteria colonies during this change? Should I do anything to prevent a big die-off, if one would even happen?

 

[IKeepPacu]

i would try to lower the temp as slow as possbile. since you want to lower it 7* i would turn the heater down by a degree or 2 every day. and make sure you have a fish in there that can handle the temperature drop over the week to keep your bacteria fed. a feeder or pond goldfish would work well for this purpose.

could you lower the temp faster without any major die-offs?? possibly. but im not sure its worth risking losing an already established tank IMO

 

[DemonShark]

It used to be a tropical tank, so there is still some fish waste in there. I could put in small amounts of ammonia to now and then too. Would I still need to add some fish though?

 

[lighthouse39183]

Not if you are adding ammonia. You would basically be doing a fishless cycle, except you are just keeping your BB fed during this process.

 

[IKeepPacu]

Not if you are adding ammonia. You would basically be doing a fishless cycle, except you are just keeping your BB fed during this process.

exactly. just make sure you get 100% pure ammonia, no scents or anything else.