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I decided that I would likle to try to breed my cory's ( 7 skunks 5 spotted and 5 juli's). Well I did the whole water change with cold water and since 2 of my skunks have died. About 1/3 of all my corys started to fatten up is this egg production or sickness. The rest are kind of sluggish. Since I started to get the temp back to normal. It was about a 8-10 degree drop. I know this was not the best idea in hindsight. But everyone I talked to said to use the coldest water I could get out of the tap and thought thiss was a little extreme so I didnt go that far. I feel really bad for these guys but they don't show any external problems?
Please help
Thanks
2cool

you never said what the original temp was before you dropped the temp. and i would never suggest that you drop the temp that fast again (which i am sure you figured out). think of it as you dropping the pH or raising it real fast. not a good idea. too much shock. i would suggest that you slowly (very slowy) increase the temp in the tank. from the book i just read, next time, reduce the temp about 2 degrees within about 2 hours. i degree per hour. that is supposed to work. what do the corydoras gods think

You have three species that possibly come from three different habitats, I'm not sure about the so called 'spotted' ones, there 60 or more species you could call spotted coming from all over the SA continent. It is always advisable to attempt breeding with a single species set up, that way you can monitor the results of your actions. To attempt a mass spawning of several species is not a good idea because whats good for one species is not necessaraly good for another

Cool or even really cold water changes are the clasic way of triggering Corydoras into spawning mode, but the timing needs to be right. I would not think that the influx of cold water would have caused the demise of your two C. arcuatus, but it depends on how you did the change.

Assuming the fish look like they are in breeding condition and again depending on the species, my recomendation would have been to reduce the water level by 40 - 50% and then re-fill with water that is 8-10 degrees cooler, leaving the heater in place. This would then alow the water temperature to return to what it was fairly quickly.

Below is a link to the spawning Log on C. arcuatus, this gives all the details from when I first bred them.
http://corydoras.pwp.blueyonder.co.uk/s ... 013%20.htm

Hope this helps.

Ian