ok i did a 20 percent water change yesterday and everything looked fine and then today i looked at my CBS (coral banded shrimp) started to turn yellow and then tonight he finally died i dont no wat caused its death and im really really nervous for my angel and my clown and my two chromies and my sea erchin please tell me what happended or tell me something to do tonight PLEASE HELP IM ASKIN ANYONE FOR ANY KIND OF HELP