Fish owners know that decor is an important part of personalising an aquarium. Castles, rocks and houses make a fish tank fun. Some fish need or prefer caves and other places to hide. However, aquarium decorations can chip and fade over time. Many people like to repaint aquarium decor to make it fresh and new, and some people even create and paint their own aquarium decor. Painting aquarium decorations takes some thought. Some paints can be harmful to fish, and some paints don't do well underwater.
Find the appropriate paint. Epoxy paint is a popular choice. The Idaho National Engineering and Environmental Laboratory states that epoxy paint will cure underwater. It is also safe for fish. Another safe choice is acrylic latex paint. Look for paints labelled non-toxic, and do not use an oil-based paint.
Rinse your aquarium decoration in cold water and remove any algae. Dry completely.
Spread newspaper or other covering over your work area. This will allow you to concentrate on painting rather than having to worry about drips. Be sure your work area is in a place where it can stay for a few days undisturbed.
Use a paint brush or sponge to paint your aquarium decor. Be sure to cover the surface completely. A sponge is useful for getting paint into grooves or cracks.
Allow the aquarium decoration to dry for two or three days. Even if the paint is dry, it may not be cured. Allowing the decor to dry for a longer period of time will help it resist flaking in your aquarium.
When in doubt, ask an expert. Call your local aquarium supply store with any questions.