What type of resin and paint is used in making aquarium ornaments?
You would have to get some kind of non-toxic, waterproof, marine grade paint. To buy that kind of paint in a variety of colors would probably be very expensive. If you are interested in making or painting your own aquarium decorations, you might want to try what I did. Instead of investing in aquarium-safe paints and clays in a variety of colors, I just use regular polymer clays and acrylic paints and then coat them in clear, marine-grade epoxy resin. It’s great stuff! It air dries and seals the clay and paint so that it’s safe for the fish and anything I seal with it is completely waterproof. I’ve made a lot of my own aquarium ornaments and pleco caves. I bought mine from Tap Plastics online, but you might be able to find some locally. Call around to boat stores and ask for clear, marine-grade resin.
