MOLLY SICK

Question
I BOUGHT 5 NEW MOLLIES AND 6 NEW GUPPIES ON TUESDAY,5 OF MY GUPPIES HAVE JUST DIED AND NOW 1 OF MY MOLLIES IS SICK SHE HAS WHITE MARKS LIKE COTTON WHOOL ON ALL ITS FINS AND IS STAYING AT THE BOTTOM OF MY TANK. I'VE HAD MY TANK FOR MONTHS AND THE PH LEVELS ARE FINE CAN YOU PLEASE TELL ME WHY ALL MY FISH ARE DYEING.ITS A 60 LTR TANK WITH NOW  17 FISH WHO ARE ALL QUITE SMALL STILL. THE LARGEST FISH I HAVE ARE 2 SILVER SHARKS.

Answer
Hi Lisa:  I would start with getting the water chemistry checked.  Sometimes adding fish into a tank will cause the water chemistry to spike, especially when you add more then 5-6 fish at a time.  I would do a 30% water change and add some aquarium salt. The white stringy strands can be caused by chemicals as well as parasites or fungus... The easiest to determine is the water chemistry... let me know... dave