My shark has picked off one tank mate I believe. The shark was the last fish I added to my tank and the fist fish I added was a Melanurus thinking he will be able to effectively hide.... Well after having him for over a year and then adding the shark, he disappeared in a week..... now is it the shark? im not sure because the sand sifting goby is still alive and frequently sits by the shark but the timing lines upHave your sharks never picked off tank mates?