That's going to leach calcium and carbonate into the water. It'd be wicked cool to do a Tanganyika tank with a pile of skulls in it, though. More likely to be a natural habitat near the northern shoreline of Lake Victoria, though.
Calcium and carbonates isn't the only thing going to be leeched into your aquarium. Remember you have a small amount of water with a large amount of decay going on if you approach it that way... so it would still be harmful to your fish... even african cichlids.
The treatment of a human skull, especially if coming from a medical school, is going to have exposure to various preservation chemicals, all which would be highly toxic to fish and other animals.
So, rotting bone aside... still deadly, still gross!
On the side note, while I do not like the idea having human bones in the tank, this thread makes me laugh. Funniest thread I have ever read!!! It's a fact you cannot deny. Now who would ever place a real skull in the tank and then a ghost coming out to possess you?
But if I do seriously consider this thread, I'll award it for being the "Funniest Thread of the Year".
Seems like some people think this is more strange than it is. People put fake skulls in their tanks, so why is a real one more gross? Its not, its just more authentic! Also, as for the decay issue, in the movies dead bodies under water are always preserved - do bones decay faster or slower in water?
lol that would be awsome to run air bubbles through the skull and it would be sick looking, to put a moonlight over it at nightime. I know everytime i look at it i would just wonder whos skull it used to be. and what that person used to be like(did they evern like fish tanks)
And by the way when you found the skull on ebay what were you reaserching?
Cause in my mind i see you looking for a kidney for uncle eddie sick in the hospatal