Aquarium Water Temperature

It was a terrible accident waiting to happen because of my work schedule, which is also quite erratic. I discovered to my 'surprise' that my planted tank's water temperature has risen so high 35 to 36 degrees. And the worst part, it got nothing to do with equipment failure - I am using Jager's heater (an Eheim brand) which is really the most reliable one can get hold of - but I totally forgot that during the last water change, I turned the heater to max intending to hasten the increase in temperature for the new water and completely forgot all about it for two days. Two days and fishes started dying off on me. I started to check on all the components of my system and there it was - temperature was way off what would be considered as part of the range of what would be ideal, way off the mark with 10 degrees. For fishes like corydora sterbai, they weren't affected (so far and in terms of mortalities) because they do require higher temperature than c. melinis and others that died. Will further update you on the after-effects of the 10 degree increase in water temperature in two days time.