If you’re putting anything inside your aquarium, you should know what it’s made of. Not all plastics are created equal — and the wrong material can leach chemicals into your water, harm your fish, or break down into microplastics over time.
At Vyro 3D, we print most of our aquarium accessories in PETG — and there’s a specific reason for that. Here’s what aquarium hobbyists need to know about 3D printing materials and water safety.
What Is PETG?
PETG stands for Polyethylene Terephthalate Glycol. If that sounds familiar, it’s because PET (without the G) is the same material used in food-safe water bottles and food containers. The added glycol modification makes it easier to 3D print while keeping all of the safety properties.
In practical terms, PETG is:
Non-toxic — no harmful chemicals leach into water, even over months and years of submersion
Chemically inert — won’t react with your water, won’t affect pH, hardness, or mineral content
UV resistant — won’t yellow or become brittle under aquarium LED lighting
Water resistant — doesn’t absorb water or swell over time
Durable — stronger than PLA, with better layer adhesion that holds up to wear
PETG vs. PLA for Aquariums
PLA is the most common 3D printing material, and you’ll see plenty of sellers offering PLA aquarium decorations. It’s technically safe short-term — PLA is plant-based and non-toxic. But here’s the problem:
PETG — Recommended
✓ Holds up underwater for years
✓ Won’t degrade or soften
✓ UV resistant under tank lights
✓ Stronger layer bonds
✓ Safe for freshwater, saltwater, and reef
PLA — Use with Caution
⚠ Can soften in warm water (above 80°F)
⚠ Biodegrades slowly — can break down over months
⚠ Weaker layer adhesion when wet long-term
⚠ Can develop algae growth in crevices
⚠ Better suited for dry terrarium decor
Bottom line: if it’s going underwater, use PETG. If it’s staying dry (like a terrarium ledge in a low-humidity setup or a desk accessory), PLA is perfectly fine.
Materials to Avoid in Aquariums
Not all 3D printing filaments are safe for aquatic use. Here’s what to stay away from:
ABS — Can leach styrene, a known toxin. Not safe for submersion. Fine for RV parts and dry use only.
Resin prints (SLA/DLP) — Uncured resin is toxic to aquatic life. Even fully cured resin prints are debated in the hobby. Stick to filament-based (FDM) prints.
Painted or coated prints — Unless the paint is specifically aquarium-safe (like Plasti Dip or aquarium-grade epoxy), avoid putting painted 3D prints in your tank.
Filaments with additives — Glow-in-the-dark, color-changing, wood-fill, and metal-fill filaments may contain additives that aren’t safe for aquatic environments. Use pure, additive-free PETG.
How Vyro 3D Handles Aquarium Safety
Every aquarium product in our shop is printed with these principles:
Pure PETG filament — no additives, no dyes that could leach, no mystery materials
No paint or coatings — the color you see is the filament itself
Smooth edges — we design with fish and shrimp safety in mind, no sharp points that could injure fins or antennae
Rinse before use — we recommend giving every part a quick rinse in warm water before adding to your tank, just to remove any surface dust from printing and shipping
Ready to upgrade your tank with accessories that are actually designed for aquarium use? Check out our full lineup of aquarium-safe products.
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