They need to be grown outdoors in full sun, not in terrariums.
When temps consistently are below freezing I move my plants to an unheated garage. No light, soil just barely damp to avoid the plants rotting when dormant.
The red coloration was most likely because of the plant flowering. They will turn red before the flowers. After the plant flowers the red coloration will slowly dissipate back to green.
This usually when the mother plant will pup.
Some species the mother will continue to grow after flowering...