Coconut as a coral mount?

[Lypto]

I've got a bit of aged coconut shell I use for projects, and the outermost shell, after the rough husk has been sanded down it is really quite hard and tough without being treated at all. I'm wondering if it can be used to mount some kind of soft coral or if I can polish it with a cloth and create a very interesting aquascape. Its been in water for about 3 years and the outer shell didn't degrade visibly. If anyone had tried with something like this I'd love to hear about it. 

[OPtasia]

I've used coconut shells as breeder caves for cichlids like Kribensis. IMHO, the shells will degrade and dissolve over time although it could take years for them to degrade and decompose. When this is happening, there's two issues i'd be worried about. The first is nutrients and the second is pH. As the shells degrade, they will be adding nutrients to your tank and the acidic decomposition will also negatively affect the pH, causing it to drop over time. Coconuts are designed for ocean travel. They're very buoyant with a tough outer skin that's designed to float in ocean water. It's how coconut trees have spread all over the tropics and the planet. They drop into the water, float away, then wash up on another beach somewhere and take root.