Hi I have a 30 gallon tank set up with a filter and a heater set at about 78 degrees. I have all fancy guppies in there and that's only 10. I bought a few new ones (still makes it ten) yesterday and today I came home to find that there are three of them with loss of color and the tails are clearing and deteriorating. I have no idea on what to do. I have made water changes and checked levels since I set it up the first time, is it a fungus or bacteria? I really need some help with these guys and girls, my daughter just loves them and I can't lose any of them and disappoint her... Please help me.