I have purchased from saltwaterfish.com several times, its actually where I get most of my fish. I have had some fish die BUT it was probably due to tank conditions rather then shipping. I did not want to go through the trouble of returning them so I cant say how the guarantee is. They ship them in bags with oxygen sealed with metal clamps, I have never had any problems with a busted bag or leaking. Also, after so many orders you get free things......got something free today with my order (puffer) which is why I am here on message boards trying to find out about levels and free items. I would highly recommend this website for ordering. Keep in mind that LFS order the same way and they too get dead fish on arrival! Good Luck on the tank! :happyfish