They are nano gobies and most only live maybe 3 years. But the really short lived ones were probably harassed and hid rather than ate. I'd make sure you get a fat and happy one and put it in first, maybe with a couple green chromis or fire fish. Give it a good month to settle in and make sure it is taking prepared foods as well (nori & cyclopeeze were favorites of mine, though a friend swears by nutrimar ova for nano gobies). Mine had no issues eating, but I have heard of some not eating prepared foods.
Do be careful with the clowns, mine is an unholy terror and will be removed from the tank as soon as I can catch her. This same percula was the one that caused me to find the Hector's goby a new home, and she's doubled in size since then. She's bested a couple wrasses and a royal gramma. All of them at least 50% bigger than herself.
Great tank mates for other semi-aggressive or small aggressive fish, but not good peace keepers. At this point I can either keep her, or have multiple fish in the tank. Not both.