Aquarium Safe 3D Print Material: Choosing the Right Options

Different 3d print filament spools showcasing the materials for aquarium designs custom 3d print

3D Printing Materials: Safe and Unsafe Choices for Aquariums and Terrariums

February 7, 2025 3D Print Filaments Insights Comments (0)

3D printing has opened up endless possibilities for customizing aquariums and terrariums. Whether you’re crafting unique decorations, functional components, or habitat enhancements, 3D printing allows for unmatched creativity. However, not all materials are suitable for these environments, especially when considering the safety of your aquatic or terrestrial pets.

When selecting aquarium safe 3D print material, it’s crucial to consider both the aesthetics and the safety of your aquatic pets.

In this article, we’ll explore the most common 3D printing materials, including aquarium safe 3D print material, discuss their suitability for aquariums and terrariums, and share practical insights based on my personal experience and online research – such as why sealing / coating your aquarium / terrarium 3D prints is NOT a good solution. A detailed comparison chart and guidelines for material selection are also included to help you make informed decisions.

Table of Contents

Understanding Aquarium Safe 3D Print Material

For over 2.5 years, I’ve tested a variety of 3D printed objects in aquariums, from decorative planters to functional caves. This hands-on experience taught me that while most materials can initially seem safe, their behavior over time varies significantly.

For example, PLA, a popular material, showed limitations. I created adjustable aquarium planters with PLA, which worked fine at first but became brittle after a few months underwater. The degradation led to breakage, and I wouldn’t recommend it for long-term submerged use. However, scientific studies indicate that PLA does not form persistent microplastics in real-world aquatic environments, as hydrolysis may prevent long-term fragmentation.

In contrast, objects made with PETG performed exceptionally well. Even after extended periods in both freshwater and saltwater aquariums, PETG decorations remained intact and safe, showing no signs of degradation. Additionally, plecos enjoyed grazing on the microorganisms that naturally grew on the PETG surfaces, proving their compatibility with aquatic life.

These observations align with studies on material properties, which emphasize the importance of choosing the right 3D printing filament for aquatic or terrarium use.

Comparing 3D Printing Materials for Aquariums and Terrariums

To help you choose the most suitable material for your projects, here’s a side-by-side comparison of the most common 3D printing materials:

Material	Durability in Water	Safety	Best For	Limitations
PLA	Becomes brittle over time	Safe initially	Short-term projects or decorative elements	Not durable in water, prone to breakage
PETG	Highly durable and water-resistant	Safe and non-toxic	Long-term use, freshwater, and saltwater setups	Avoid exposure to extreme heat (above 80°C)
ABS	Durable, but leaches harmful chemicals	Not recommended due to styrene release	Functional, non-submerged parts with no pet contact	Requires food-safe coating, but still poses risks
Polycarbonate (PC)	High strength and water resistance	Potentially unsafe due to BPA	Specialized high-strength applications	BPA presence can be harmful to aquatic life
Nylon	Strong, flexible, but absorbs water	Generally not recommended	Temporary parts that do not stay submerged	Absorbs water, weakens over time

Why Material Purity Matters

It’s important to note that not all PLA, PETG or ABS filaments are created equal. Many manufacturers add fillers, dyes or other additives to enhance properties like flexibility, color or strength. However, these additives can pose a significant risk when used in aquariums or terrariums, as they may release toxic chemicals into the environment.

Pro Tip: Always choose plain, food-safe materials without harmful additives for 3D printed objects in aquariums. Look for certifications like FDA-approved or food-safe ratings and avoid filaments marketed for industrial use (unless you are confident, they contain no harmful substances toxic to fish and amphibians). Also, for safety, avoid filaments with bright red, orange or neon colors, as some of these could contain cadmium-based dyes.

Why Sealing Your 3D Prints is NOT a Good Idea for Aquariums

When it comes to making ABS plastics safe for use in aquariums or terrariums, many sources recommend sealing them with epoxy resin or similar coatings. While some high-quality epoxy resins (e.g., FDA-approved brands) may perform better, this method is still unreliable long-term. Based on personal experience, extensive research and insights from the 3D printing community, sealing ABS is not a reliable or long-term solution.

Here’s why sealing your ABS prints may actually cause more harm than good:

1. Poor Adhesion of Sealants

ABS plastics have a low surface energy, making it difficult for most adhesives or coatings to stick effectively. Even if a sealant seems to bond initially, the constant exposure to water, humidity, and temperature fluctuations in an aquarium can cause the coating to peel or detach over time.

Real-World Example: Many hobbyists report that epoxy coatings, touted as reliable sealants, begin to fail after just a few months of use, leaving their 3D printed objects exposed.

2. Time-Consuming and Unreliable Preparation

To even attempt a proper seal, the entire surface of the ABS print needs to be meticulously prepared. This involves:

Sanding the surface to ensure better adhesion.
Cleaning it thoroughly to remove oils, dust, and residues.
Applying the sealant evenly to cover all surfaces, including hard-to-reach crevices.

Even with careful application, there is no guarantee of long-term success, as small imperfections during preparation can lead to weak spots in the coating.

3. Structural Limitations of 3D Prints

Most aquarium or terrarium decorations are designed with thin walls or flexible structures to reduce material usage and enhance aesthetics. This introduces additional challenges:

Flexibility Over Time: ABS softens at typical aquarium temperatures (24–28°C). This means any bending or movement during cleaning can cause the sealant to crack or peel.
Fractures and Weak Points: Even robust designs can experience stress fractures in their coating over time, particularly in high-humidity environments or with frequent handling.

Key Insight: Even with high-quality sealants, the risks of peeling, chemical leaching, and structural failure make sealing an unreliable method. Additionally, particles from failing sealants can contaminate aquariums, requiring deep cleaning.

The Better Alternative: Start with Non-Toxic Filaments

Instead of relying on complex and unreliable sealing methods, the best solution is to use non-toxic, food-safe filaments like PETG from the start. Here’s why:

No Need for Sealing – PETG is naturally durable, water-resistant, and safe for long-term use in aquariums without additional coatings.
Reduced Risks: By eliminating sealants, you also eliminate the risk of peeling or chemical leaching caused by a failing coating.
Ease of Use – Food-safe PETG filaments are widely available and require no extra preparation beyond printing.

A custom design 3D printed aquarium cave using aquarium safe 3d printing material - PETG

Best Practices for Using 3D Printed Objects in Aquariums

Choose the Right Material: Opt for PETG or food-safe ABS for long-term projects. Use PLA only for short-term applications where durability isn’t critical.
Monitor for Degradation: Regularly inspect your 3D printed objects for signs of wear, especially if they’re submerged in water.
Prioritize Simplicity: Avoid using overly complex designs with tight crevices that may trap debris or compromise structural integrity underwater.

Conclusion: Choosing the Best Material for Your Needs

After extensive testing and research, it’s clear that PETG stands out as the best material for long-term use in aquariums and terrariums. Its durability, non-toxicity, and water resistance make it the most reliable option for both freshwater and saltwater setups.

While PLA can be used for short-term projects, its tendency to degrade over time limits its practicality in submerged environments. ABS is strongly discouraged, as even sealed prints may still pose toxicity risks. Polycarbonate (PC) and Nylon, while occasionally marketed as aquarium-safe, have significant drawbacks, such as BPA content and water absorption.

By choosing the right materials and following best practices, you can confidently integrate 3D printed designs into your aquarium or terrarium without compromising the safety or well-being of your pets.