I keep them in the low-mid 70's most of the time. I moved the pair into an unheated 29 in the basement the last time they spawned to save the fry, then back into the 75 with the severums, pleco's, etc. after the tank started getting crowded by the growing fry. The juvies are in unheated tanks in the basement now, but the temp doesn't seem to affect them much either way.