Nope, we didn't touch it at all after. Just deactivated it and put it away. This didn't stop it from spawning in if we joined the server at night though.
It doesn't come in every night, only the first initial night that we spawn in if we spawn in at night. If we spawn in during the day, it doesn't come at all during our round of playing, even the following night. It only comes if we spawn into the server while it's already night, it's just there, lurking. And it disappears by morning and doesn't come back for the rest of our gaming session.
And for clarification- we don't want it to spawn, we want it to stop automatically being there if the server starts up at night, even though the terrarium is inactive. If it starts up during the day, it doesn't spawn at all during that gaming period, even during the nights. The only condition that it spawns under (without us activating the terrarium) is if the server happens to start up when it's night.