Starfish in tank

You should be fine, though I'd suspect that over time the star would degrade to nothing. I'd give it a good gentle wash first. Start slow too perhaps, with some testing fish.

if you do also watch the ph close I think the stars has a calcium carbonate skeleton somewhat simialiar to a seashell. which can effect the PH level I will see if I can find something to support it.

Mike

the only thing that I can find out so far is that it will effect the ALK in the tank buffers will help in keeping it all in check but unless its a african chiclid tank with a higher PH. the dead coral is diffenatly calcium carbonate which of course will effect PH but will take some time before it starts to degrade and effect it.
basically in SW alot of people use crushed coral because its buffereing quality to help keep the PH at around 8.0-8.2. small pieces have less effect but over time will effect it buffers might not always work to keep it inline.
I have a post in a reef forumn that I go to a lot to see if anyone knows exactly what effect and exactly what the skeleton is made of. there is a resident star expert over there that will know I just dont know when she will be back online to answer. I will post it over here when it gets answered.
Mike

I'm with VoodooChild. It probably won't hurt anything, but will probably rot and fall apart.

havent heard or found anything else out but the break down starts at a certain PH but Im not sure at what level. but I would think a couple of months before it really starts to get bad but only doing it will actuall tell because I have never heard of this being asked before so to me its all new. LOL
Mike