I'm currently making some fake rocks for an aquarium, so it is not about garters, but I tought that it might interested some of you. I got a skates tank and I want to improve the decoration. So I start 2 fake rocks to partially split the tank in 2.

The tanks size is about 6 feet wide X 12 feet long and 2 feet depth. It inhabitants are 2 barndoor skates, 6 winter skates, 1 shorthorn sculpin, 1 sea raven and plenty of waved whelks (scavenger). The fake rock will serve a separation in the middle of the tank (with a way between the rock for the animal to pass) to keep the food on the side where I feed them, it is mostly to simplifies the cleaning of the food in over.

Here an overview of the tank in question




For the fake rocks, I use styrofoam to give the overall shape, then I coat it with sikatop 121, who is a waterproof cement.

That one without the cement on it :




And with a coat of cement on it


The next steps will be to coat the hollow inside of them, then maybe a second coat on it with some cement pigment. I will add some weight inside to make sure they don't float.

I still have to wait some weeks to make sure the cement is well dry, and then I will put it underwater.

So this technique can be use to make smaller or bigger decorative element for your garters enclosures, it is way lighter than true rock (and it is pretty easy to do).