What exactly causes finrot to occur?? Does temperature have anything to do with it? How can you prevent finrot from happening?

Thanks in advance.

Fin rot is cause by several different types of gram negative bacteria and ofter occurs together with other diseases. Fin rot occur when the fish is stressed for some reason, but the most common cause is poor water quality. Overcrowding the tank, feeding outdated food or overfeeding, and moving or handling the fish can also cause stress leading to fin rot. The only way I can see temperature being a culprit is if it has been changed drastically. The best cure is prevention, and by keeping the water quality perfect with frequent water changes and lots of gravel vacuuming you will not have any problems.