Peppered Cories look unwell

[Greg5530]

Help I have 4 peppered Cory's that look unhealthy, I have had the tank for a couple months now and the Cory's were doing great and now they are kind of just sitting still and not moving much, they do not even budge when food is put in. The tank is maintained at 79 degrees but it got really cold last night and dropped down to 72-74, nitrites were kind of high so I did a 40% water change. Ammonia was at 0 and nitrites were at .50-1, I started off with a fish less cycle, any help would be appreciated.

 

[Calypso77]

Your nitrites should be 0 if the tank is cycled and that temp drop may have not been good for them. Do you not have a heater? What are your nitrates testing at?

 

[Greg5530]

I have a heater it just got really cold last night and the heater was having trouble keeping the temp normal, after the water change my nitrates are at 20 ppm

 

[Calypso77]

Hmmm so it almost sounds like your nitrates were probably higher before the water change. Not too sure how high though if it could have been in a danger zone.

 

[Greg5530]

Well I put one in the breeder tank to adoid him getting stuck by the filter I will check levels tomorrow and do another water change if needed anything else I should do in the meantime

 

[Greg5530]

So 3 of the cories have died just one left

 

[HN1]

Sorry for your losses.

You need to establish the tank a bit more I think. Also, those cories prefer cooler water than 79, think 74-76. The sudden change may have been the final straw though.