Interesting. Have you come up with a definitive answer since originally posting? I just had a clownfish entirely disappear from my tank, and he was the only fish IN the tank! Plus a smallish hermit crab, 2 other small crabs, and a couple of snails. He didn't jump into the filter or out of the tank, and there are no remains to be found. He was there this morning, so somebody did a quick and thorough number on him. Would/could a hermit crab attack, kill and fully eat a clownfish in a day?