In addition, a lot of snakeheadd are subtropical. They will continue to fight and feed normally in temps down to low 50's.
In addition, you will not be able to reintroduce the female back without loss. The male will not recognize her, and she will not recognize and feed her fry later on. In fact, she may even eat them.
The fry can swim freely from one side to the other.
In addition, it's now too late to put your female snakehead back. A snakehead has the ability to recover from the most serious injuries GIVEN that its water conditions don't change much. For example, no water changes, low fluctuations in temp and ph, no meds, no salt, and most importantly, no new water. Changes in water stress out a snakehead, and that's when they start to grow fungus. By you putting it in another tank, you have just stressed the hell out of it. If you put it back into its original tank now, you will stress it out even more. Like I said, it's very normal for snakehead pairs to fight after breeding. My female pulchra got beat the crap out of after breeding both times. It fully recovered both times. Many people's snakeheads fight after breeding. The female is usually very weak after laying eggs, and the male is usually much stronger, and has the advantage. You should have let them sort out their own business. Even if you were to reintroduce her back in a month or two, the male will not even recognize her, and therefore will fight because they are no longer a pair. She will be seen as a threat to his saftey, like introducing a new fish into an established tank.
Snakehead fry are very sensiti
ve to water changes, including drastic temp changes. Lowering temps may do more harm than good. Big water changes, salt, meds, will wipe out fry.