The item ID for Firefly in a Bottle is 1993
If there is no item ID, please use the item name to spawn.
This is the spawn command to give yourself Firefly in a Bottle in Terraria. Terraria does not have a vanilla item spawn command and varies between singleplayer and multiplayer. For singleplayer you can use the inventory editor. For mutiplayer you can use a plugin or mod like TShock.
Example spawn commands that will work with TShock:
Copy the command below and paste it into your Terraria game or server admin console to obtain.