Thanks for the replies!
I'd be afraid that bones & antlers would rot, flake, fracture, raise the pH of the water and just generally not work out very well. Mind you, I've never tried it.
A good point Bruce_S, and one of the things that concern me, but I've found horse/cow ribs and vertebrae in the creek behind my home, some of them over a year old, and they'd held together rather well, though the creek is
dry for a large portion of the year.
I guess we'll see?
If the bone is aged you the organic component should be gone. You will be left with mostly hydroxyapatite (Ca10(PO4)6(OH)2).
It will leech both PO4 and Calcium in water. This will be sped up significantly in acidic water. I can not speak to how significant these amounts would be with reasonably timed water changes.
Thanks for the science approach Sotty :] This is certainly along the lines of what I was hypothesizing, and with the aged, fully dried bones, they ought to be completely "dead" and ought to hold together. That's how fossils are made, right?
Or coat them in silicone.
A cool idea, psalm18.2. I wonder if there is a thinner silicone sealant out there you could do this with? Or maybe a way to thin down the silicone yourself? I'd just be sad that moss couldn't be attached, but then again, stark white antlers (or even a small ribcage) stabbing out into the water, as semi-carnivorous fish frolic among them is a rather enticing idea all its own >:}
[...] to be safe i would clean them up and place them in a bucket and leave it for a week and then test the params.
Definitely a good idea for anything 'experimental' a practical Aquarist is wanting to add to their aquarium :] Thanks for the advice stevenjohn21!