How to Seal and Waterproof Terrarium Decorations for Aquatic Use

August 23, 2026

3D-printed and porous ornaments are perfect in a dry terrarium, but for anything with standing water, a paludarium pool, a water feature or a full aquarium, they need waterproofing first. This guide explains how to seal terrarium decorations for aquatic use, step by step. It expands on our terrarium-decor-in-an-aquarium guide.

When do you need to seal?

Sealing is only needed for permanent or frequent water contact. In a dry or humid terrarium or vivarium, a rinse is enough. Seal when a piece will be submerged, sit in a pool, or take constant splash.

What to seal with

Aquarium-safe epoxy resin - the most durable, glass-clear finish.
Two-part polyurethane - tough and water-tight.
Food-safe / aquarium-rated silicone - for sealing joins and bases.

Always choose a product explicitly rated aquarium-safe once cured.

Step by step

Clean and dry the ornament completely, sealant won't bond to a damp surface.
Apply a thin, even coat over every surface, including the underside.
Add a second coat once the first is touch-dry for full coverage.
Cure fully - 24–72 hours per the product instructions. Don't rush.
Soak-test in a bucket for 24–48 hours, watching for bubbles, clouding or film, before it joins your display.

large temple ornament sealed for aquarium use — Tihe Hall Chinese Temple - seal a piece like this before it goes into a paludarium pool or aquarium

A note on our pieces

Fish Bazaar ornaments are 3D-printed rigid plastic - terrarium-ready as-is, and aquarium-ready after the sealing steps above. A Chinese Wide Gate (₹449) sealed this way makes a striking submerged archway.

sealed wide gate ornament for aquarium — Chinese Wide Gate - once sealed and cured, a gate becomes a striking underwater archway

Conclusion

Seal only what meets water, use an aquarium-rated epoxy or polyurethane, cure fully and soak-test. Done right, one ornament serves both your dry and aquatic builds.

Decor for water and land. Explore Fish Bazaar's 3D-printed range, made in India, shipped nationwide.

FAQ

How do you waterproof a terrarium ornament for an aquarium? Clean and dry it, apply two thin coats of aquarium-safe epoxy or polyurethane, cure fully, then soak-test before use.

Do terrarium decorations need sealing? Only for permanent water contact. In a dry or humid terrarium, a rinse is enough.

What sealant is safe for aquariums? Epoxy resin, two-part polyurethane or silicone that is explicitly rated aquarium-safe once cured.