# Unglazed, fired clay OK for tanks?



## Shaky (Jan 2, 2003)

I have access to a kiln and made some clay caves. When fired, without glaze, will they be OK to add to the aquariums?
I'm hoping its completely inert and wont alter the water chemistry.

Its standard white clay used in classrooms and schools.


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## Anthraxx8500 (Feb 11, 2011)

pretty sure even glazed can work. seen some really neat art turned aquarium deco.. it has to be a certain kind of glaze but im not sure. hopefully someone else will chime in.


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## DJRansome (Oct 29, 2005)

IDK either. Terra cotta pots work. Do you know the content of the clay?


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## Shaky (Jan 2, 2003)

I called the clay shop and asked this question.
They said that all earthenware will eventually break down, but it won't soften and "melt."
It will break down by tiny bits, algae will grow on it, etc. Eventually it will "return to the Earth from whence it came."
I'm not sure how long this process will take, but I figure they may last a year or so before I have to remover them.


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## JAyliffe (Feb 29, 2012)

They still find Amphora from Rome in the ground so I'm thinking it takes a few years at least :lol:


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## DJRansome (Oct 29, 2005)

I was thinking more about lead content in the clay, you know how they tell you not to use certain pottery for food use. But I don't even know if lead would be harmful to the fish.


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## UNIDEKE (Apr 15, 2012)

I have made some caves out of the very clay you are talking about (bisque). I did glaze them with dinnerware safe, lead free glaze. My fish love them! I noticed a couple spots I missed covering with glaze...they seem to be holding up fine. Will look to post pictures soon...

-Deke


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## Shaky (Jan 2, 2003)

These were my first try. Left a small opening in the rear of each to allow fry to escape should a "stranger" enter the cave.


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## deaver (Apr 23, 2011)

opcorn:


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## NeptunesNeighborhood (Apr 19, 2012)

Shaky said:


> These were my first try. Left a small opening in the rear of each to allow fry to escape should a "stranger" enter the cave.


very cool :thumb:


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## UNIDEKE (Apr 15, 2012)

UNIDEKE said:


> I have made some caves out of the very clay you are talking about (bisque). I did glaze them with dinnerware safe, lead free glaze. My fish love them! I noticed a couple spots I missed covering with glaze...they seem to be holding up fine. Will look to post pictures soon...
> 
> -Deke


Here are a few pictures...not the best quality...I took them with my phone  I did pick up more clay and plan to make some more in a few weeks. The dinnerware glaze has limited "natural" colors, but these didn't turn out too bad. Might try the earthenware clay and use the grey-speckled glaze...I think the darker color clay will darken the lighter glazes up a bit...all trial and error at this point. My water chemistry is doing fine. I did soak them for a few days and wiped them off before I put them in the tank...my water chemistry has been spot on for weeks now (but I don't test for lead). I think you'll be ok, but I suggest you glaze them. You can get dinnerware-lead free glaze on Amazon. I use this kind: http://www.amaco.com/shop/category-49-low-fire-cone-05-glazes.html Good Luck, let me know if I can clarify anything.


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## Shaky (Jan 2, 2003)

Thanks for the advice, UNIDEKE
Here are the finished caves. Still unglazed, and I'm not sure I plan on glazing, although I do have access to lead-free glaze in several colors.
(thanks to the school art teacher)
I'm not really sure how best to utilize the caves, though.
It may be that I don't use them until September - that's when I plan to set up the Tanganyikan 20G tank in the classroom.


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