Question - Coral breakdown in aquarium

[jred]

A friend of mine brought back a piece of coral (or what I believe to be coral) that looks like a dried out fan - I was thinking of doing a nano tank with some shrimp that could crawl all around the piece of coral. My only thought was would it break down in our freshwater? I know we have a decent pH so I think it would take a long time to break down but maybe some other people can give some perspective on the matter. Thanks in advance!

[phish]

I think it will dissolve when you are under a certain PH. Like say your PH is 8.0, it won't dissolve but if your PH is 7.0 then it will dissolve. I think it will stop dissolving around PH 7.5 or so.  I haven't checked in a long time but PH out of tap used to be 7.0

[freshwater]

I have had coral in some of my tanks for years at a PH of 7.5 have not noticed any break down