my wife wants a starfish..which one should i buy?

Probably much longer than that.

Point is, there's a chance in that 120 gallon tank that an orange may be ok. The LPS tank at this fish store is smaller than 120, for sure. It's only like 12" deep. It's probably got 30-40 lbs of live rock, if that.

 

I think a lot of people would be interested in knowing more about these stars, Seano. As of right now we don't even know what they feed on. You'll read that they eat biofilm, but from what I've read--we really don't know. I'd be very surprised if anyone knew how long they survive in the wild.

My buddy had one in his SPS tank that was very fat and happy for at least 6 months. He broke down his tank and gave the star to me. It was dead within 2 months. Such a shame to see it just wither away. Never lost its color until it died. It grew thin so slowly, I had to pull it out twice and sniff it just to see if it was still alive.

 

You need to do some research to determine for yourself which starfish is right for you. Some eat algae, some eat detritus, some will thrive on leftovers, and some won't survive without shellfish to feed on. Once you've decided on the type of food you can provide, then you can choose from the list of stars that will survive with that.

Hope this helps