They are very easy to keep, as long as you can give them a cooling period. I keep them in an unheated tank with cool water live bearers
all winter, where the temp hangs around 65'F. In summer I toss them in the pond where they have spawned the last couple years.
I put them in the pond last week,(except the brooding female)
this I consider their cooling off period.
temps are now high 40s low 50s at night, low 60s day time.