thats what sucks about keeping live fish is that they die. sometimes we know what its from other times we cant figure it out. it really sucks you lost all of your rays and im sorry for your loss. it feels like you just want to give up but after you enjoy the rest of your fish and give it some time im sure you will jump back in with some rays. the same type of stuff happend to me i wish i still had the ones i lost but this time im doing everything right and am happy with what i have. so hang in there it all works out in the end.