Clown missing

I went on vacation for 9 days, 3 days ago my mother texted me saying one of my corals has some white spots on it. Had her send a pic to me. I was nothing much but in the pic was both clowns. Got home late lastnight and one clown is missing, tore the tank apart looking for a body, not a trace. Could it of been consumed with in 3 days to nothing? Didnt jump out, made a full proof feeding door for her to dump in measured food. I have 1 cleaner shrimp, 2 very small blue leg hermits, a dozen snails, a few small bad crabs amd a very small hitchiker pistol shrimp plus whatever i dont know of.... On my other tank the ATO went out the day after we left. I tested it for 1 month before and sure enough I got a text saying the water was evaporating out and not replenishing. The **** hose popped off the pump, easy fix but dang....