My tank was swimming with pods long before a year as well, but I tried a mandarin with 50 lbs. of rock after my tank was up for about four months and he decimated every pod in my tank within two weeks. I had thousands of pods, but they were all gone. I even had a good refugium he could not get too, but that only kept him alive for another four months. He slowly withered away. Granted, mine was in bad shape when I got him, but you won't find too many fat ones in stores. Most are already on their way to starvation: their bellies are already deeply sunken in.
I speak from experience and what I have heard.
A friend of mine, whom I know personally, has a 180 gallon tank with 250 lbs. of live rock and his died after about nine months. He introduced it when the tank was six months old. His was a fat four inch mandarin when he got him and it died from starvation as well; its fat belly slowly got skinnier and skinnier until it was completely sunken and one day he died.