What Can You Put in a Terrarium? A Complete Guide to Terrarium Decoration Ideas

Introduction

A terrarium is a sealed or semi-sealed glass container that holds a small, self-sustaining landscape of plants and, increasingly, a carefully composed miniature world. The decorations you choose do three jobs at once: they set the theme, they create scale and depth, and in a pet enclosure they give animals places to shelter, climb and explore. If you have ever looked at your empty glass jar and wondered what to put in a terrarium beyond a plant or two, this guide walks through every layer and every category of decoration, from the practical substrate at the bottom to the ornament that becomes the centrepiece.

This is a top-of-funnel primer written for beginners, but it is detailed enough that seasoned hobbyists will find useful placement and scale principles too.

What goes into a terrarium, layer by layer

Before decoration comes structure. A healthy decorative terrarium is usually built in four layers, bottom to top:

1. Drainage layer - leca (clay balls), gravel or pebbles, roughly 2–4 cm, so excess water drains away from roots.
2. Barrier layer - a mesh or fine screen that stops substrate falling into the drainage.
3. Substrate layer - a growing medium suited to your plants (a coco-coir/orchid-bark mix for tropical, a sandy mix for desert).
4. Decoration / hardscape layer - everything you see: rocks, wood, moss and ornaments.

Understanding these layers matters for decoration because your ornaments sit on or are bedded into the top layer, and heavier centrepieces should be seated firmly into the substrate so they cannot shift or topple.

Category 1 - Natural hardscape

Natural materials are the traditional backbone of terrarium decor:

• Rocks and stone - dragon stone, seiryu, slate and river pebbles build elevation and ledges.
• Driftwood and cork bark - add organic lines and climbing surfaces; cork bark is a favourite for arboreal (tree-dwelling) setups.
• Moss - sheet moss, cushion moss and preserved moss carpet the floor and soften every edge.

Natural hardscape looks beautiful, but it has trade-offs: real wood can rot or grow mould in a humid, sealed terrarium, and untreated rocks may leach minerals. This is exactly why many hobbyists now blend natural materials with inert, man-made ornaments that hold their shape and never decay.

Category 2 - Ornaments and focal points

An ornament is what turns a planted jar into a scene. This is where you introduce story and theme, a temple emerging from moss, a gate framing a path, a boat run aground on a sandy shore. A good focal-point ornament should:

• Match the scale of the container (more on this below),
• Read clearly from the front viewing angle, and
• Be made from a safe, inert material that won't harm plants or animals.

Fish Bazaar's 3D-printed Asian-architecture range was designed for exactly this role. A few that work especially well as terrarium focal points:

• Torii Gate - a Japanese shrine gate, 10 × 9.5 cm, that works as a framing archway near the front of a scene so everything behind it gains depth. From ₹299.
• 3-Story Pagoda - a tiered pagoda, 8.5 × 7.5 × 7.5 cm, in a classic red-and-black temple palette; a natural single hero for a medium display. ₹799.
• Ancient Chinese Home - a cosy courtyard cottage, ~5.5 × 5 cm, that groups into a village when you use several. ₹329.
• Ancient Viewing Platform - a raised open terrace, 7.5 × 6.5 cm, that sits beautifully on a rock ledge or the crest of a substrate slope. ₹449.

Each is 3D-printed in rigid, non-toxic plastic and hand-finished, so the detail stays crisp, and importantly for a terrarium, it is ready to use as-is in a dry terrarium or vivarium and will not rot or mould like natural wood.

Category 3 - Themed and story pieces

Once you move past a single ornament, you can build a theme. Popular directions:

• Temple / ruins theme - a pagoda or temple half-buried in moss, with a gate and a cottage suggesting an abandoned village.
• Riverside theme - a stilt house and a boat, such as the Dragon Boat, arranged along a sand "shoreline".
• Zen garden theme - a single minimalist pavilion with raked sand and a few stones.

The strength of a themed approach is coherence: every piece supports one story, which reads far better than a scatter of unrelated objects.

How to get scale and depth right

Scale is the single most common beginner mistake. A few rules that instantly improve a layout:

• Match ornament size to container size. In a small or pico terrarium, a 4 cm piece looks right; a 12 cm tower will swamp it.
• Place larger pieces toward the back, smaller ones toward the front, to force perspective and make the scene feel deeper than it is.
• Leave negative space. Plants and (in a vivarium) animals need room; an over-decorated terrarium looks cluttered and stresses livestock.
• Use the rule of thirds. Set your hero ornament off-centre rather than dead middle.

Terrarium vs vivarium vs aquarium, does the decor overlap?

A frequent question and a genuinely useful one for choosing decor is how these enclosures differ:

The practical takeaway: a well-made inert ornament can move across all three, but anything going into water permanently needs a waterproof seal, whereas in a terrarium or vivarium it can go straight in. (We cover sealing in the buyer's guide.)

Conclusion & next steps

Building a terrarium is really two decisions stacked on top of each other: the functional layers that keep it alive, and the decoration layer that gives it character. Start with a solid drainage-to-substrate base, choose one clear theme, get your scale right, and anchor the scene with a focal-point ornament that won't decay. New to safe materials, or ready to buy? See our pet-safe terrarium decorations guide and our 3D-printed buyer's guide.

Ready to give your terrarium a centrepiece? Explore Fish Bazaar's 3D-printed Aquarium & Terrarium Decor range, unique, hand-finished pieces you won't find in the usual shops, delivered across India.

FAQ (FAQPage schema-ready)

What can I put inside a terrarium? A terrarium can hold a drainage layer, substrate, live or preserved plants, natural hardscape (rocks, driftwood, moss), and inert ornaments such as 3D-printed miniature buildings that add theme and scale.

How do I decorate a terrarium without plants? Lead with hardscape: use sand or gravel, rocks, and a strong focal-point ornament (a temple, gate or cottage). Non-living materials give a clean, low-maintenance scene that needs no watering.

What are some unique terrarium ideas? Build a themed miniature world, a ruined temple in moss, a riverside village with a boat, or a Zen garden with a single pavilion, using scaled ornaments placed by the rule of thirds.

What should I not put in a terrarium? Avoid untreated softwoods that rot, sharp objects that could injure animals, painted items that may leach, and anything too large for the container. (See our full pet-safe decorations guide.)