Anyone know how to make Fake Coral?

Question

I have a nice 60 gallon bowfront and would like to create a certain design. I assume fake coral is concrete and I think I could make something look decent, but I dont know what type of concrete is used or how to go about it. Any suggestions?

Answer 1

Are you making this for a freshwater or saltwater tank? Your first concern should be getting a material that would be safe for your fish. Cement would be likely to break down in high salt concentrations (ever see what happens to a cement sidewalk after a few winters of throwing out salt to melt ice?) and the carbonates from the limestone would break down in freshwater and could raise your pH. Plus if you don't want it to be white, you'd need to find a water-safe paint that won't leach dyes or other harmful materials.

Most of the hard fake coral decorations you see in pet stores are actually made of a plastic resin so they won't react to the water chemistry. There are some "soft" ones as well that seem to move with the water current made from another plasitc/latex type material.

If you want to try making some, I'd recommend that you try using an aquarium-safe epoxy: http://www.bigalsonline.com/BigAlsUS/ctl3684/cp18270/si1379843/cl0/instantoceanholdfastepoxystick4oz or http://www.bigalsonline.com/BigAlsUS/ctl3684/cp18270/si1383217/cl0/twolittlefishiesaquastikredcoraline2oz . They are workable like putty to shape and will stick to a piece of stone for a base. The first will dry to an off white, the second to a reddish color and both will cure underwater in about 30 minutes. Both are totally aquarium safe.

You might just find it easier to buy a good looking piece, but depending on the size you are looking to make, they can be rather expensive.