should left 1 .
will like to answer question here.
normally stay at 1 ft below light , normal flow rate, and will not move once it like the place (base my 3 year with anomeny). light 4 X t5
I never feed, but nemo feed it.
I have mid high no3, and once chiller pump not working reach 30 degree, non of them have problem, as hardy as it is.