Making clay caves for aquarium fish...

i don't think they'll work, but you can try some home testing to see if obvious stuff happens - like does it melt in water? etc.

pick a clay you're curious of, make something, and BEFORE adding it to a tank of water, check the water for basics like PH and calicum with regular swimming pool water test kits.

assuming your piece doesn't melt in water, confirm the piece doesn't shift the water properties like PH & calcium, etc.

see ya

steve

Luckily, I have a kiln, so I will be making my own decorations and stuff for our coming (SOOOON!!) aquariums.

There are clays that have to be oven-baked, which might not give off as much "stuff" as air-dry clays. You also have that plastic stuff that just needs to be heated a little in order to dry hard, and that seems then very durable.

But I second Steve that you need to put a piece in a water sample that you test before and after - and long after! You don't want to poison your fish in the attempts :-)

Marianne

I use polymer clay for snow globes and, since it is a polymer plastic, it is ideal for permanent placement in a water/oil situation. The toxicity, however, is not a consideration in a sealed application so I can't say if that would be an issue for you or not.

Best of luck with the fishies! Lori

From experience, I would opt for fired clay, the higher temperature the better, rather than anything else. Air dried clays are not, in my experience, water resistant, and I would avoid anything that cold cures because of possible chemical release.

I used to make pieces for a local aquarium shop, and we found that the safest option was cone 8/9 stoneware, as it is largely resistant to any contamination. Porous materials aren't!

Steve Bath UK