However, there are clays that harden at lower oven temperatures so you don’t need to super hot kiln type oven. Instead, you can use a regular home baking oven. With that in mind, you might try Sculpey. It’s a type of ‘clay’ that’s made of type of plastic. You harden it in a regular home oven, but a much lower temp than a kiln.

Visit the web site below to get more information about Sculpey and if it’s right for you. However, because it’s a type of plastic, it may work well in the fish tank. Before placing anything into your fish tank, though, you should contact the company, for any material you choose, to ensure that the material isn’t dangerous for the fish.

It’s also possible that because Sculpey is plastic, you may not even need to harden it before putting it into the fish tank. But, as I said, you’ll want to check to make sure it’s not dangerous for the fish.

Good luck with your project.

or for a faster drying clay look at this website:

http://www.dragonsaretooseldom.com/craft_clay.html