I understand how you feel, I am a beginner fish keeper and followed everything correctly and got 9 guppies(5 adults and 4 fry) I acclimated them in the water for 30 mins and let me out. Over the next week and a half I lost 7 guppies. They stop eating and die but I found symptoms but I was too late with the medication. The symptoms were white poop, bloating, and they were floating on the side and at the top. It was parasites, the fish I got from the start were infected and it spread to the other fish killing so many guppies and their babies. I’m going to continue to treat the remainder Babies for another week before I stock the 20 gallon with healthy fish like mollies, corys, or more guppies. This a common thing among fish keeping and keep at it. Keep your eye on weird things happing to your fish and google it, also, check your sources where you get your fish, I got mine from pet supermarket and they were infected, get yours from more reliable sources like pet smart and petco.I have a 20 gallon tank, with gravel substrate, few plants including hornwort (due to running high nitrate). I have or should i say, had several guppies, during the past 24 hours have lost 5 adults and numerous fry. after finding the first three dead, yesterday, with no apparent cause i did a 50% water change,added 1 1/2 tbs aquarium salt to the tank, then noticed a small "fuzzy" area on one of the males, i treated the tank with Tetra Fungus Guard, this morning i found another 2 dead and most of the fry not there. all the ones left are swimming at the top of the tank with exaggerated movements, put the carbon filter back in thinking i had a toxin.
water temp is 78 degrees, tank is 8 months old, but had the fish for the past 2 months with only occasional fatality
ammonia is 0
nitrite is 0
nitrate is 10ppm
ph is 6.4 (stable at that range)
what do i need to do to save the last 5, any help appreciated