Terrariums And Cages Mod
This engaging mod enriches Minecraft with various containers for keeping creatures: terrariums, cages, aquariums, and even lava tanks. They allow you to create living exhibits with your favorite mobs.

A special feature of the mod is the terrarium key, which allows you to control the visibility of container walls. When using this tool, inactive transparent walls are displayed only as outlines, providing a complete view of the contents.
Adjacent containers of different types can merge into single structures, opening limitless possibilities for design. For maximum functionality, structures of at least 3x3x1 blocks are recommended.

To decorate the interior space, simply temporarily remove the container block, place decorative elements, and then restore the walls using the terrarium key.
This functionality was originally part of the developer's other project.