if so, are there any special steps i need to do?
try this site. Cement rocks are fine for an aquarium as well as for a pond. Cement does not leach lime once cured. You can mix cement on your own find unique molds or just create something with your hands and let cure for 7 days clean while soft then let sit for another 7 no sealing required.
If the mix you were using was guarenteed to not leak anything into the water it would be fine.
I would highly highly (double to really emphasize it) not recommend doing it. Either buy/find rocks or use sand a substrate to replace it.
i dont think you should if you see in fish tank stores you might see that most ornaments are made of plastic or just live plants, i think you could try but i really suggest you dont, what if it affects the fish, if you google it maybe youl find an answer, well if you do try dont put like a whole bunch of fish in your aquarium (just incase) then again I could be wrong, just be careful, good luck!
Wow, how is this person supposed to know what to do? Seriously, go and buy BOMIX 15 or whatever, just standard GRAVEL, PORTLAND CEMENT and SAND. It should contain nothing else. It comes in 66 pound bags at home depot. Then, when it has cured as hard as it will get (couple of days/weeks) let it soak in a tub of water for a few days, changing the water occasionally to clean it. Then put it in with your fish. That is the standard procedure for my fish and I've had fishies die from ornaments from the pet store, so be careful who you trust with your pets.
