Key Takeaways

  • Filament types: Some filaments are toxic-free and water-resistant, such as pure PETG and food-safe ABS or PLA. Others may leach chemicals or degrade in water, such as nylon or resin.
  • Filament brands: Choose reputable and high-quality brands that are FDA-approved or food-safe. Avoid filaments with toxic additives or dyes, such as glow-in-the-dark filaments.
  • Filament sealants: Apply a food-safe epoxy resin or spray-on coolant to waterproof and protect your 3D printed objects from moisture and bacteria. Use a light and even coat to avoid drips and runs.
  • Filament ideas: You can 3D print functional or decorative items for your aquarium, such as tools, parts, covers, monuments, or theme parks. Use your creativity and imagination to enhance your aquarium.

There are some things you can’t put in an aquarium. Fish are sensitive, and any small slip-up can cause illness or worse in your fish tank. A recent trend is to 3D print something and use it as decor in your aquarium. But how safe is that?

3D-printed objects are aquarium-safe if they’re printed with toxic-free filament. The best toxic-free filament to use is pure PETG and food-safe ABS or PLA. But since PLA isn’t waterproof, you need to apply a food-safe epoxy resin or spray-on coolant on a PLA object before putting it in an aquarium.

It can be overwhelming to know which 3D-printed objects can go in your aquarium. I’ll try to clear the air on this topic so you can confidently print aquarium-safe 3D objects. But first, let’s talk about filaments.

FilamentAquarium Safe?Notes
PLAYes, if food-safeCoat with epoxy resin for long-term use
ABSYes, if FDA-approvedAvoid toxic dyes
NylonNoAbsorbs water, swells, and deforms
PETGYesNaturally non-toxic and durable
ResinNoCan leach toxins if not fully cured

What Filaments Are Safe For Aquariums? 

What Filaments Are Safe For Aquariums
Source: Pinterest

There are different filaments you can use to print aquarium 3D parts, each with its own set of precautions. Let’s find out more.

Is PLA Safe For Aquariums? 

You can use food-safe PLA in your aquarium for years without any problems for your fish. If you’re not sure whether your brand is food-safe, make sure you coat the 3D-printed part with food-safe epoxy resin before using it in the aquarium. 

3D printed Bonsai made with PLA
Source: Quora

PLA is a popular, biodegradable thermoplastic derived from natural substances like corn and sugarcane. But because it’s not petroleum-based, PLA is not waterproof. 

It’s biodegradable, but not that biodegradable. When you submerge a PLA-printed part in water, it won’t exactly dissolve, but it will gradually absorb some water and swell up. This will usually happen over a few days or weeks, but it shouldn’t be a problem for an aquarium environment. 

The only real issue is when PLA stays in water for more than a couple of years. This is when it starts to break down a little into the water. 

When this happens, it can introduce dangerous foreign chemicals into your aquarium because some PLA filaments, such as glow-in-the-dark filaments, have toxic additives.

To be on the safe side, use only the best PLA brands you can get your hands on. Specifically, check whether the PLA brand is food-safe. If you want to eliminate any doubts, the best thing to do is waterproof your PLA-printed part with food-safe epoxy resin.

Epoxy resin sticks to most materials to give them a glossy finish. It seals any porous holes in the PLA object to prevent water from reacting with it. 

But tread carefully when choosing epoxy resin because it often contains toxic chemicals that can kill your fish. Go for food-safe brands and make sure you cure the 3D-printed part long enough in the sun before inserting it into the aquarium.

Is ABS Safe For Aquariums?

ABS is safe for aquariums if the filament is FDA-approved. Other filaments will require you to waterproof them with a food-safe epoxy resin or spray-on coolant before using them in an aquarium.

3D printed Aquarium Overflow Box made with ABS filament
Source: YouTube

ABS is commonly used for making objects that can withstand chemical attacks and hot temperatures. But you can still use it to print objects for your aquarium because it’s much stronger than PLA.

But keep in mind that ABS is not waterproof and may leach chemicals into the water. So make sure there are no toxic dyes in whatever ABS filament you buy. FDA-approved ABS filaments are the safest option. 

Also, be on the lookout for black or white ABS because it is usually pure, making it good for aquatic life.

Is Nylon Safe For Aquariums? 

Nylon might be tough and durable, but it’s not ideal for aquarium use. Unless it’s coated with an aquarium-safe paint or epoxy resin, nylon absorbs water and swells up, disfiguring your 3D-printed part. 

Nylon is extremely hygroscopic, meaning it absorbs water quickly. When submerged in water, nylon can absorb water up to a tenth of its weight, causing a change in its shape. Again, this isn’t a real issue for an aquarium owner unless your 3D-printed part serves a functional purpose. 

For example, if you print a part to cover a pipe inside the aquarium, that slight expansion can make it loose. 

But if you’re printing a piece of aquarium decor out of nylon, you won’t face any serious challenges because of the swelling. Nonetheless, you can coat your nylon 3D pieces with a food-safe epoxy resin to prevent them from absorbing water.

Is PETG Safe For Aquariums?

PETG is absolutely safe for aquariums. One of PETG’s selling points is its non-toxicity, making it harmless to fish. In addition, PETG is tough, durable, and heat-resistant. 

3D printed Mushroom Cage made with PETG filament
Source: Printedreef

What makes it the safest option for aquariums is the fact that it’s food-safe. In its pure form, PETG is used to make human food covers and plastic bottles because it contains no toxins that can contaminate food.

Fish can also benefit from these characteristics. PETG is also non-biodegradable so it will not be broken down by bacteria and living organisms in the aquarium. 

Is Resin Safe for Aquariums?

Resin is generally not safe for aquariums. If a resin 3D printed part doesn’t cure thoroughly, it can release toxins that are harmful to the fish.

In its uncured form, 3D printer resin is notoriously toxic to aquatic ecosystems. The compounds in liquid resin can cause adverse health effects and deaths in fish. Resin 3D-printed parts may also contain some uncured micro-particles even after long UV light exposure. 

One study exposed zebrafish embryos to resin 3D-printed parts. They found that most did not hatch, and those that did had severe deformities.

When to Use a Sealant

Applying a food-safe sealant ensures prints made are fully watertight by sealing any small gaps between layers.

PLA and ABS both absorb moisture, so using a sealant will help prevent them from gradually breaking down over time.

This is especially important for any structural prints like attachments or housings where water infiltration could compromise the integrity. But even decorative PLA and ABS objects will benefit from a sealant to keep looking their best

For PETG, which is naturally water-resistant, a sealant provides an extra barrier and smooth finish but is not required.

Which Sealant Do I Need?

Here are my top 3 recommendations for sealants that can be used to waterproof 3D printed objects for aquarium use:

Krylon Crystal Clear Acrylic Spray – Best for quick protection and non-yellowing finish. The fast drying time makes it ideal for smooth even coats on decorative prints.

Rust-Oleum Specialty Clear Gloss Spray – Best for functional prints needing robust sealing and durable, long-lasting protection. The high gloss finish improves abrasion resistance.

Mod Podge Waterbase Sealant – Safest household option for indoor use. Low odor and easy cleanup with water when wet. Ideal for family projects on decorative prints.

Proper Spraying Technique for Sealants

When applying spray sealants to 3D printed objects, use a light, even coat to avoid drips and runs.

Hold the can 6-10 inches away and spray in quick short bursts, moving the can continuously over the surface.

It’s better to apply multiple thin coats rather than one thick, wet coat. Allow each coat to dry fully before adding another. Rotate the printed object to spray all sides.

Avoid holding the can too close or spraying too heavily in one area – this can lead to sealant dripping or pooling.

Take your time to apply the sealant carefully for smooth, professional results. Doing test sprays on scrap material can help dial in the optimal distance and spray pattern.

What Are The Best Filaments To Buy For Aquariums? 

Now that we know which filament types are safe for an aquarium, let’s see which brands you can try.

Best PLA filament For Aquariums

Hatchbox PLA 

Hatchbox PLA

Hatchbox PLA is what you get when arguably the most popular filament supplier creates the most popular filament. Hatchbox makes are top-drawer products that you can get without breaking the bank.

The Hatchbox PLA is hands-down the safest PLA filament you can use in your aquarium. It’s plant-based and contains a careful blend of environmentally-friendly polymers.

Hatchbox PLA
$24.99 ($0.71 / Ounce)
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MatterHackers PRO Series

MatterHackers PRO Series

Matterhackers is another industry-leading filament manufacturer based in California. The MatterHackers PRO Series is one of the most reliable filament lines you’ll find on the market, especially their PLA.

The PLA in this series is made from a patented biopolymer that is very low in toxicity, making it safe for your aquarium’s livestock. While it goes head-to-head with the Hatchbox PLA in terms of aquarium safety, the MatterHackers PRO Series PLA is notoriously prone to stringing.

MatterHackers PRO Series
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Best ABS filament for Aquariums

Hatchbox ABS

Hatchbox ABS

With Hatchbox’s ABS filaments, you can expect color variety, durability, and high-quality finishes in your 3D prints. As far as its aquarium safety, it’s 100% non-hazardous. Their range of colors will take your creative possibilities to the next level by giving you more options for things to print.

Hatchbox ABS
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03/07/2024 01:34 pm GMT

Sunlu ABS

Sunlu ABS

Sunlu ABS is a cheaper ABS filament alternative that is safe to use in your aquarium. It also comes in several color options and there haven’t been many printing issues reported with it.

Some people have complained about the printed parts being unusually brittle, but that’s generally an ABS thing. In terms of quality, Sunlu is good enough for making aquarium objects.

SUNLU ABS 3D Printer Filament
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Best PETG Filament for Aquariums

MatterHackers build PETG 

MatterHackers build PETG 

This is the industry gold standard for affordable PETG filaments. Budget-friendly but still durable, the filament usually doesn’t have the regular stringing issues associated with PETG. It’s also water-insoluble and non-toxic, so it’s more than safe for printing aquarium objects.

Overall, this is the go-to filament for 3D printing any sort of object for your aquarium.

Prusament PETG

Prusament PETG

Prusament PETG is perfect for aquariums because of its low water absorption and zero toxicity. I also have to mention that it’s manufactured by Prussa, a reputable name in the 3D printing community. Like other PETG brands, it comes in a ton of colors with different shade varieties in each color.

Prusament Jet Black, PETG Filament 1.75mm 1kg Spool
$72.00 ($2.04 / Ounce)
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What Can I Use My 3D Printer For In An Aquarium?

You can 3D print items to serve a functional or decorative purpose in your aquarium. 

Functional items are those tools, parts, and covers that help in the maintenance of the aquarium setup. 

Here are some functional parts that a 3D printer can create for an aquarium: 

  • Feeding funnels
  • Hose clamp
  • Bubble maker
  • Airline holder
  • Sand flattener
  • Water test kit rack

Decorative items mainly improve your aquarium aesthetics, although they also give fish a place to reproduce. With decorations, the ideas are infinite. You can create famous monuments or an entire theme park for your fish to live in.

Here are some decorative ideas you can 3D print for an aquarium:

  • Faux rocks
  • Castles
  • Guard towers
  • Caves
  • Branches and sticks
  • Stone Walls
  • “No Fishing” sign

In some cases, 3D printing an object is much cheaper than buying it, especially the smaller ones. And there are situations where it’s nearly impossible to find the exact decor you want in a pet shop, let alone one that is aquarium-safe.

What Are The Best 3D Printers For Aquarium Decorations?

As we’ve seen, filaments play a huge role in determining what is safe for your aquarium. But having the right printer puts a cherry on top of your overall 3D printing experience. 

Here are the best 3D printers you can use for your aquariums:

Creality Ender 3 V2 

Creality Ender 3 V2 

The Creality Ender 3 V2 is designed to give the best value for money in an entry-level 3D printer. Sophisticated enough to handle complex models but simple enough for a first-timer to use, this 3D printer is an excellent budget pick for most people.

When it comes to everyday 3D printing, Ender 3s are known to bring a lot to the table, including a large build volume of 220 x 220 x 25 0mm for you to print large prints in one go.

Its resume printing function allows you to jump right back into your printing session even after a power interruption or outage. This is something you don’t get on cheaper printers.

Top budget 3D printer
Creality Ender 3 V2 3D Printer

Upgraded version of the original Ender 3 with a number of key improvements.

This easy to assemble DIY kit creates a 220 x 220 x 250mm build volume for printing epic creations. Experience ultra-quiet operation and stable, precise printing with the upgraded motherboard and extruder.

And, get great first layers with the heated carborundum glass print surface.

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Prusa i3 MK3S+

Prusa i3 MK3S+

The Prusa i3 MK3S+ comes at a more hefty price tag but for a good reason. 

Overall, the machine is built with superior components that push the envelope of quality for printers in its price range. The Prusa i3 MK3S+ is a high performer capable of printing for long hours without degrading quality. 

It might have a slightly smaller build volume of 210 x 210 x 250 mm, but it makes up for it by printing at record-breaking speeds. If you’re willing to spend some extra cash, the Prusa i3 MK3S+ will give you a more premium experience than the Ender 3 V2.

Top 3D printer kit
Original Prusa i3 MK3S+ kit

Meet the gold standard in DIY printing - the Prusa i3 MK3S+!

Print like a pro with exotic filaments like PC and nylon thanks to the 300°C hotend.

Reliable, precise, and loaded with innovations like auto bed leveling, the Prusa i3 MK3S+ delivers exceptional performance right out of the box!

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Can you put 3D-printed things in the water?

You can put 3D-printed things in water, provided they are made out of the right filament. If it’s going to go into water, the object should be made out of toxic-free filament such as pure PETG or food-safe ABS and PLA.

Can I use PLA in my fish tank?

You can use PLA in your fish tank if the PLA is food-safe. If you’re not sure whether your PLA brand is food-safe, make sure you coat the 3D-printed part with food-safe epoxy resin before using it in the aquarium. 

Is 3D-printed PLA waterproof?

3D-printed PLA is not waterproof. When PLA stays long enough in water, it begins to break down. 

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