Fish safe 3D filament

[Goldie Blue]

I am wanting to get some 3D printed decorations for my tank made, and I need some advice on the proper filament. If it helps, I am looking to get a blown up version of The One Ring (ideally close to the pic below with someone holding it), and the party sign from Lord of the Rings printed out, so it'd need to be colored filament.

My neighbor has a 3D printer and offered to try to make these for me, but I want to be double sure that we use fish-safe materials, and I know literally nothing about 3D printing so any help would be awesome. 

[Kiefer]

Look into food safe filaments, anything considered food safe would almost certainly be safe in an aquarium. That said, I think the majority of filaments would be fish safe. People worry far too much about what's safe and not in your tank, meanwhile their natural habitats (and random ditches in florida where they're invasive) are full of random human garbage and many aquarium species still manage to hack it.

[darkG]

One solution is to coat the finished piece in food grade (or known fish safe) resin. (Potentially wax could suffice?). 

But one factor in food safety is smoothness, to limit bacterial build-up. That doesn't apply to aquarium safety. Food stuff may also be expected to withstand hot water. So food-safe is a high bar. 

Your neighbor probably won't be able to print most materials anyway. 

The common base plastics are probably not too bad though. Some pigments and other additives, plasticisers, could potentially be a problem. Unfortunately, it will be hard to find out for certain. 

I would probably risk using most materials myself for my own use, increasingly less so with fancier stuff such as metal-filled, sparkling, flexible, carbon fiber, glow in the dark, bright red or orange, flame retardant. 

Good luck! 

[TheDukeAnumber1]

@Goldie Blue

The most common filaments types are PLA, PETG, and ABS, all of which are fish tank safe. I've been mixing printing and aquarium use for a good while and you don't have much to worry about.

[Goldie Blue]

Thanks for the replies! I will let you know how it goes. 

[Esotericbyte]

Do tell! how did it go?