To add terrarium to firestick, you must ensure that your system fulfills all the basic system requirements mentioned below. They are as follows-
You will need an alternative media player on your firestick device to play the media.
Your firestick device should have the developer settings enabled. If it is not enabled by default, navigate the Settings option, then click on My device, go to the Apps from Unknown services option and then click on the “Enable it” feature.
Also, if you have any pre-installed terrarium versions installed on your device, you need to uninstall them immediately. Otherwise, the application will not work effectively.
You need to make sure that your Firestick device has an active and stable internet connection.