Question

Do good bacteria in a fish tank filter die off in twenty minutes when filter is turned off? ​

Answer 1

It is not a good idea to turn off your aquarium filter every night. The filter plays a key role in the health of your tank, and shutting it down for hours at a time can eventually lead to problems.

Answer 2

Like your fish, the microbes in your tank are pretty hardy. Turning off the filter for a night now and then isn't going to hurt them much. But if you do it every night you are depriving your fish and the microbes of oxygen for eight hours out of every twenty-four, and that will eventually catch up with them.