My tank was fine foe a few months. I had guppies and a few mollies. Out of nowhere the male guppies started dying about one a day or every other day. I bought the recommended meds and aquarium salt. They seemed okay for a couple of weeks then I started finding them dead again, The females had fry so I didn't buy any more males. The females then started dying. Mollies were finOnce the females died I still had the fry. As the fry got to where they were maturing and showing their colors, they died. I did everything according to what I read online. Meds, Salt, water changes, so I gave up on guppies. But I like guppies. Any suggestions? I;m going to buy a 55 gal tank soon and i'd like to have guppies. The tank I have is 30 gal and was given to me by a neighbor who said he couldn't keep anything alive in it except and Oscar. Whice he gave to someone else. I've had tanks on and off for many years and never had this problem before.