[OrangeAugust]

I have a 55 gallon tank and a few months ago I dealt with about 3/4 of my fish dying after I got some new platies and didn't quarantine them. I did a bunch of water changes and then everything seemed ok. A month or so later I would get random fish deaths. A month ago all my cories died almost at the same time. I think they might have gotten poisoned because I had never vacuumed the gravel when I have done water changes. Anyway, everything was fine for a couple more weeks and then my dwarf gourami started acting weird and died a few days later. and then two platies died within the next week.
I have been having a hard time keeping the temperature in the right range. AqAdvisor advised 75 degrees but my heater sucks and I had it set at 72 but the water wouldn't go below 82. Could this be the reason why some of my fish are dying? Will temps that are a few degrees above what they should be cause fish death?
Thanks!

 

[Romad]

Could be. Were they gasping at the surface? If you're having trouble keeping the temp down, add an airstone to help oxygenate the water.

The obvious solution is to get a better heater